SHOULD YOU DO HIIT TO GET FIT?

Posted on March 6, 2017 by sbromlow

Have you ever found yourself at the gym on an elliptical or treadmill wondering if there was better and faster way to do cardio for fat loss? A new style of training known as high intensity interval training (HIIT) might just be your solution. Many fitness bloggers who advocate HIIT say that it is better than moderate intensity steady state (MISS) cardio because it burns more calories in a shorter amount of time as well as increases your metabolism and burns calories even after you are done working out due to something called the EPOC effect. On the other hand, there are some people who say that moderate intensity steady state cardio is better than HIIT cardio because MISS primarily uses lipids as a fuel source, and therefore burns more fat. But is one really better than the other?

In 1996, Dr. Izumi Tabata performed a study on the effects of moderate intensity training and HIIT, in order to better understand which method was more effective for preparing olympic athletes for events. For his experiment, he studied two groups. The first group exercised at 70% of their VO_2maxfive times a week on a treadmill. He compared this protocol with the Tabata protocol and found that the Tabata group was exercising at an intensity of 170% VO_2max. In the end, the two groups both had increases in aerobic capacity, but when anaerobic fitness was analyzed, the Tabata protocol group increased by 28% while the other group remained the same. This means that high-intensity interval training actually improves both anaerobic (muscle building) and aerobic (fat burning) body systems, while moderate intensity exercise only improves the aerobic system. Additionally, the Tabata group lost more weight on average and gained more muscle than the MISS group. The results obtained from this study ultimately helped legitimize a movement away from chronic cardio and toward high-intensity workouts.

SO, WHAT IS HIIT?

HIIT is a type of training in which intensity and heart rate is varied throughout a workout, as opposed to MISS which is exercising on a treadmill, elliptical, etc. and maintaining your heart rate around 125 bpm for 30 to 60 minutes. During the high intensity intervals, your heart rate should be around at least 160 beats per minute, and during the low intensity intervals around 100 bpm. A typical HIIT workout might look something like this:

Exercise 1: Push-ups

Exercise 2: Jump Squats

Exercise 3: Burpees

Exercise 4: V-ups

Start with push-ups. Perform them for 20 seconds at a high-intensity. Rest for 10 seconds, and then go back to doing push-ups for 20 seconds. Once you complete eight sets of push-ups, rest for one minute. Next, move on to jump squats and repeat the sequence of 20 seconds on, 10 seconds off. Once you finish eight sets of jump squats, rest for one minute, and then do burpees. After burpees, finish the workout with V-ups.

EPOC: Excess Post-Exercise Oxygen Consumption

Since you burn roughly the same amount of calories during a HIIT and MISS workout, The big debate over HIIT vs MISS cardio for fat loss comes down to how many calories you burn after a workout. Most of the misinformation circulating around HIIT vs MISS cardio is centered around EPOC. This term simply refers to the process of restoring your body to a normal resting state after exercising. During this time, your body uses energy and burns calories while recovering and building muscle. The big debate is whether the EPOC after doing a HIIT workout has significant effects on weight loss or not. One fitness blogger said that “new age Tabata style workouts burn 50-70 calories during a workout and 300-400 post workout over the next 24 hours.” The truth is, you are more likely to burn around 300 calories during a HIIT workout and about 40 after. The claim made above would require an EPOC of over 100%, and since EPOC generally doesn’t surpass 30%, this claim was clearly not based on scientific evidence, and can be very misleading to uniformed readers. One study reported an EPOC of 25% after a very intense and strenuous high intensity workout and 10% after a moderate intensity workout, but even though high intensity workouts have a higher EPOC than moderate intensity workouts, the amount of additional calories burned due to the EPOC effect is not very significant. It is important to keep in mind that although these numbers may appear to be convincing, the difference in calories burned, is only about 30 calories, which is much easier to achieve simply by dieting.

Even though the EPOC theory turned out to be false after all, one study did show that HIIT training increases muscle mass and therefore increases the capacity to burn fat, so in the long run, HIIT could actually be booting your metabolism. HIIT also has a lot of other health benefits to offer. For example, one study found that HIIT training greatly improved cardiovascular endurance and that subjects who went through two weeks of HIIT training experienced a drop in their resting heart rate, indicating better cardiovascular health. Some people forget that their heart is a muscle. If you keep it beating at a constant rate, then it doesn’t have to work harder, and therefore it isn’t getting any stronger. This can be a problem for people who regularly stick to the elliptical or treadmill and never reach at least 80% of their max heart rate.

Overall, there is not a big difference in the number of calories burned between HIIT and steady-state cardio, but HIIT may have some additional anaerobic and cardiovascular health benefits. Deciding whether to do HIIT versus MISS can also depend on a variety of other factors. For example, your diet. If you are on a low carb diet, or are carb cycling, you may want to do a MISS workout on low carb days rather than a HIIT workout because HIIT requires a lot of carbohydrate (glucose and glycogen), whereas MISS primarily uses lipids for energy. Also, if you are doing weightlifting in addition to cardio, MISS might be a better option because HIIT offers some of the same benefits as weightlifting. Another thing to consider is that HIIT is very strenuous, and it may be challenging to jump right into an advanced HIIT workout especially if you are just beginning an exercise program. That being said, if you are the type of person who prefers weightlifting and doesn’t need to incorporate as many body weight exercises into your workout regime to build muscle, then by all means, stick to weightlifting and steady state cardio. However, if you like doing HIIT workouts either because they take less time to do or because they don’t require any fancy gym equipment, that’s also fine. Whatever your personal fitness goals and workout preferences are, the most important thing is always to listen to your body and do what’s best for you.

Questions and comments:

Which do you personally prefer, HIIT or MISS?

If you previously did HIIT because you believed you were burning hundreds of calories post-workout, do you think you will still continue doing HIIT now that you know the after burn effect isn’t true?

Comment below if you’d like to share any thoughts about HIIT or if you have any questions.

Thanks for reading:)

Free Weight vs Machines: Is One Better Than the Other?

Posted on March 6, 2017 by adehope

Searching for the best possible way to make gains in the gym can often be tricky or overwhelming. When you walk into the gym you can probably find a wide range of weight machines along with rows of dumbbells and squat racks. Many lifters incorporate a mix of free weights and machines when they are training. Free weight exercises require balance and they allow for movement in multiple planes while weight machines provide movement over a fixed range of motion. Some people swear by free weights alone and wouldn’t dare touch an exercise machine at the gym. Others solely use weight machines in their workouts. Which method of lifting is the best way to get in shape?

The benefits of using weight machines are that they are easy to use and figure out which is especially helpful for beginners. They are considered “safe” in the sense that you will not drop a heavy weight on yourself or someone. It is also easier to change resistance and loads on a machine. However, the movements one makes on a weight machine do not imitate natural movements we make every day. The exercises done on a weight machine usually do not target large muscle groups so isolated training is required.

The advantages of free weights are that they mimic real world movements and they target larger muscle groups, working more muscles in one exercise at a time. They require the use of stabilizing muscles so one must balance to perform the exercises. This coordination is part of the reason they are more natural movements that can help in day to day activities. Common disadvantages are that they are intimidating to beginners and some exercises require a spotter.

Lifters often quantify their strength by their one repetition maximum (1RM) or the heaviest weight a muscle/muscle group can successfully lift just one time with correct form. A study published in the Journal of Strength and Conditioning compared the force produced by muscles when squatting and bench pressing free weights or in a Smith machine. The results showed that participants had a greater 1RM in squatting with a Smith machine. Alternatively, participants had a greater 1RM when bench pressing using free weights. A previous study comparing free weight squats and bench press to machines showed greater 1RM in machines than in free weights, however the differences were not significant.

Example of a man squatting under a smith machine.

Another study done by Schick et. al. (2010) was conducted to compare the activation of muscles when bench pressing on Smith machine or a free weight bench press. The results found that there was significantly greater activation of the medial deltoid in the free weight bench press than in the Smith machine bench press. The instability caused by the free weight bench press requires more use of medial deltoid to both stabilize the body and produce the force necessary to lift the weight. The results did not show differences of activation in the larger chest muscles. The study used experienced and inexperienced lifters to determine whether one exercise was better beginners or not, but they did not find any significant differences between groups. It should be noted, however, that the study defined experienced as someone who consistently benched twice a week for 6 months. It may have been more helpful to use subjects with some more time and experience lifting.

The studies conducted do not necessarily favor any mode of exercise over another. I believe that more experiments should be performed to study the long-term effects of using free weights vs machines and whether one method may lead to faster results.

When deciding on whether to choose to lift using free weights or machines, it is best to determine what your goals are. If you want to be more efficient in the gym and use the most muscles in less exercises, free weights are your best bet. If you do want to isolate certain muscles and have more time to spare weight machines will work well. Many people incorporate both free weights and machines in their workout regime. I think it is most important to keep in mind that free weights are safe and activate more muscles when performed correctly. While weight machines may help in making you stronger, they avoid working those stabilizing muscles to help with balance. So, when your buddy needs help moving his couch up 3 floors to his apartment, you might wish you trained with free weights instead.

Nah Coach, I don’t have to stretch.

Posted on March 5, 2017 by Kathryn

Ever wondered if those pre- and post- workout sessions really make a difference in your daily exercise regimen? It is commonly believed that stretching prior to and following a workout will decrease the likelihood of injury, minimize post workout pain, and increase performance. However, other athletes and trainers believe that stretching has no impact on these factors and can even decrease strength and performance. But what are the facts?

Figure 1. Examples of active and passive/static and dynamic stretching.

There are several subgroups of stretching but I will focus on performance results with regards to the two most well researched types: static versus dynamic. Each stretch can be done actively or passively, where active stretching is when you contract the muscle in opposition to the one you want to stretch and passive uses an external force such as a strap, the force of your body weight, or gravity. Each type of stretching, shown above, has been shown to impact exercise in different ways. Let’s start with the most frequently used type, static stretching, where a person slowly moves muscles until they reach the brink of pain and hold that position for 20-30 seconds.

Static stretching has been compared to continuously stretching a rubber band. Immediately after stretching the rubber band, the band remains limp as it contracts slowly back into its original form, similarly to the behavior of a muscle. It seems unrealistic to expect a maximum amount of contraction and force immediately after stretching your muscle. In more physiological terms, the loss of muscular stiffness caused by static stretching results in an increase in length of sarcomeres in each muscle fiber, decreases contact between actin and myosin, and therefore decreases the force produced (Shrier, 2004; Kokhonen et al., 2004).

Figure 2. Actin and myosin movement in relaxed muscle versus contracted muscle. The less contact between actin and myosin, the less force produced.

One study by Fletcher and Jones (2004) on 97 male rugby union players showed a significant decrease in sprint times for the passive static stretch group. This could be due the mechanical impact of stretching on the muscle, kinematic differences, or neural inhibition which decreases the neural drive to muscle. Dynamic stretching focuses on moving through a range of motion repeatedly and mimics motion that will occur during exercise. Fletcher and Jones’ (2004) study showed more beneficial performance results from active dynamic stretching prior to sprinting though. The active dynamic stretch group of rugby players improved their sprint times significantly.

These results could be explained by information in a systematic review of studies on stretching and exercise by McGowan et al. (2015). This review showed that dynamic stretching increases the temperature of the muscle more than static stretching. This increase in temperature activated an increase in muscle metabolism, elevated oxygen uptake, and increased the power output of the muscle. Another study by Gray et al. (2008) showed a correlation between increased muscle temperature and faster ATP turnover, caused by an elevated rate of creatinine phosphate utilization and H+ accumulation. The elevated muscle temperature also resulted in short term (~2 minute) increase in anaerobic glycolysis and muscle glycogenolysis. These physiological responses, in theory, would result in greater power production during sprint and sustained high-intensity exercise, however high quality research results on this topic are limited.

Several literature reviews regarding this topic exist, but compiling results from hundreds of varying studies makes it difficult to normalize the results. Several reviews analyzed results that were not statistically significant, skewing the review results. By looking at the methods researchers used to gather and compile data and at the sources they cited, I was able to identify the sources where results were significant and relevant. The review also covered studies on a span of sports from swimming, to sprinting, to jumping, all which are impacted very differently by stretching, which makes the conclusions for these reviews far reaching statements. When more studies are done within each of these sports, reviews that group together specific events and exercises will provide more beneficial results.

When looking at the impact of stretching on pain, several papers used self-reported ratings of pain to measure differences. In those studies the results did not show a significant difference between ratings from groups that stretched and controls. Self-reported measurements of pain contain bias which makes them difficult to compare between groups of people. Some papers overcame bias by observing differences in delayed muscle soreness by measuring creatine kinase levels, a commonly used marker for muscle damage. One experiment by Buroker and Schwane (1989) showed no significant difference in creatine kinase levels from stretching post-exercise. Very few studies are done solely to measure the effect of post-exercise stretching on soreness and risk of injury so it is difficult to differentiate these results from the pre-exercise stretching.

Keeping these biases and knowledge gaps in mind when considering the results of these papers, it is plausible that for the majority of exercises, dynamic stretching can positively impact your performance. This is largely due to the fact that it increases the core body temperature and targets activity in specific muscles that will be used instead of just stretching them. Static stretches prior to a workout seem to have no impact or a negative impact on performance since the muscle needs time to recover and regain stiffness before use. Personally, this would convince me to do some dynamic stretches before my next run rather than static stretches. While it differs from sport to sport, dynamic stretching appears to be the ideal pre-exercise stretch to optimize performance.

Recommended Further Reading:

1. Blahnik, Jay. Full-Body Flexibility, Second Edition. Available at: http://www.humankinetics.com/excerpts/excerpts/types-of-stretches

2. Sifferlin, Alexandra. Why Stretching May Not Help Before Exercise. (April 08, 2013) Available from: http://healthland.time.com/2013/04/08/why-stretching-may-not-help-before-exercise/

3. Shrier, Ian. Sports Med (2004) 14:267-273. Available from: http://www.elitetrack.com/article_files/stretchingreview.pdf

4. Kokkonen, J., Nelson, Α. G., Cornwell, Α. (1998). Research Quarterly for Exercise and Sport. 69 (4): 411-415. Available from: https://www.ncbi.nlm.nih.gov/pubmed/9864760

5. Fletcher, IM, Jones, B. J Strength and Condition Research. (2004) 18(4), 885-888. Available at: http://staps.nantes.free.fr/L3/entrainement/etirements/THE%20EFFECT%20OF%20DIFFERENT%20WARM-UP%20STRETCH.pdf

6. McGowan, C.J., Pyne, D.B., Thompson, K.G. et al. Sports Med (2015) 45: 1523. Available at: https://link-springer-com.udel.idm.oclc.org/article/10.1007%2Fs40279-015-0376-x

7. Gray, SR, Soderlund, K, Ferguson, RA. J Sports Sci. (2008) 26(7):701:7. Available at: https://www-ncbi-nlm-nih-gov.udel.idm.oclc.org/pubmed/18409101?dopt=Abstract

8. Buroker, KC, Schwane, JA. The Physician and Sportsmedicine (1989) 17(6): 65-83. Available from: http://www.tandfonline.com/doi/citedby/10.1080/00913847.1989.11709806?scroll=top&needAccess=true

LISS vs. HIIT Training Sessions – Can both lead to Weight Loss?

Posted on March 1, 2017 by lzak

Although exercise can provide many health benefits, many people look at it as a simple way to help them lose weight. However, intense exercise may seem daunting to populations who are new to exercise or recovering from injury. Therefore, the question arises of whether it is possible to lose weight with low intensity exercise. In this news article, published by The Telegraph, they take a look into each form of exercise and how they effect weight loss.

The author, Lucy Waterlow, claims how “the HIIT philosophy has been behind every new exercise class, bestselling book and rising YouTube fitness star” The fitness acronym stands for High Intensity Interval Training and typically requires you to keep your heart rate at at least 85% of its maximum capacity throughout the workout. However, for people with injuries of any kind this method of exercise is a bit more difficult. Therefore, LISS has been heavily emphasized as of late as being the new and improved way to keep your weight under control and putting less of a strain on your body. LISS stands for Low Intensity Steady State and requires you to keep your heart rate between 60-80% of its maximum capacity.

The article references a recent study by the University of Bath, which found that “LISS can be just as effective as HIIT when it comes to weight loss”. Theses results came from a study in which they asked people of a similar age to exercise five times a week at either high or moderate intensities. Their results showed that after a three-week period, both groups had lost the same amount of weight. Dr Jean-Philippe Walhin, a human physiology research fellow who carried out the study, quotes ‘What really matters is how many calories were used up by exercising in total.’

The articles continues with an additional argument claiming that LISS may motivate people to work out more since it isn’t as stressful on your body. This way, you are able to increase your physiological health and motivation at the same time without the high risk of injury that may occur with High Intensity Interval Training. In conclusion, the article highlights the benefit of LISS workouts and how they are comparable to HIIT workouts in weight loss.

I believe this is a relevant article to the Engineering Exercise course as it looks at two different, popular types of training and how they affect weight loss. Although “the best way to lose weight” will always be a hot topic, I think it is important to recognize that different exercises are better for different people based off of their medical history.For example, the idea of going to the gym for a cross fit class may scare someone who is obese out of working out at all. But, the idea of 45-minute brisk walk may appeal to them more and benefit them physiologically rather than not working out at all. It becomes a cross between physical therapy, where exercises are designed for the individual, and research, where the latest and greatest ideas for weight loss are tested.

In my opinion, I thought this article was interesting in its approach to the general public but was lacking in the hardcore data. However, I felt this is expected in a “Lifestyle” piece and found it interesting to see how referencing studies and quoting doctors may be enough to convince the general public about health and fitness, regardless of whether hard data was presented. When I looked into the argument of LISS vs. HIIT workouts further, I found a source that provided more detailed information to prove their points and support their argument. In Martinez’s “Cardio for Fat Loss“, he focuses on the pros and cons of each kind of training and how they benefit you in weight loss. I found this to be more beneficial than the original article as it stated straight facts about both, and let the reader decide which is better for their situation. The underlying conclusion was that “HIIT is quicker, proves to be more effective for fat loss, creates metabolic changes, and helps with muscle retention but not everybody can do HIIT. LISS is safer, but takes twice as long to accomplish similar things and it still has its place for fat loss in moderate amounts, from a pure calorie burning standpoint (meaning only to burn calories & not make changes to your metabolism)”. This was helpful in looking at weight loss from a metabolism standpoint, rather than just pure fat loss. In conclusion, it is beneficial to know that despite differences, both HIIT and LISS workouts can lead to some form of weight loss.

Reccomended for Further Reading:

Lucy Waterlow, “Ditch those heart-thumping HITT sessions: low intensity exercise is the best way to work out” February 23, 2017. Available from: http://www.telegraph.co.uk/women/health/ditch-heart-thumping-hiit-sessions-low-intensity-exercise-best/

Chris Martinez, “Cardio for Fat Loss: High Intensity Interval Training Cardio vs. Low Intensity Steady State Cardio”. February 15, 2017. Available from: http://www.simplyshredded.com/cardio-for-fat-loss-high-intensity-interval-training-cardio-vs-low-intensity-steady-state-cardio.html

Help! I’ve Sprained My Ankle…Should I call the POLICE or use RICE?

Posted on February 26, 2017 by nreisher

For anyone who’s had a sprain, you’ve probably heard of RICE, or Rest, Ice, Compression, and Elevation, to take care of your injury. Sprains are extremely common; each year, approximately 1 million people are treated with ankle sprains with costs at about $40 million per year. A sprain is a stretching or tearing of ligaments, which are fibrous tissue that connect two bones together. Common symptoms include pain, swelling, bruising, and limited mobility in the affected area. Most doctors and physical therapists recommend RICE for treatment and can be treated at home. RICE is an acronym used for patients to remember when they have sprains for treatments. They first must REST the injured area and ICE the area as soon as possible. Then they must COMPRESS the area with an elastic wrap or bandage and finally ELEVATE the injured area to avoid swelling.

Although RICE has been recommended for treatment for a long time, doctors are beginning to question RICE and are beginning to recommend POLICE for treatment. POLICE stands for protection, optimal loading, ice, compression, and elevation. Optimal loading means creating a balance and incremental rehabilitation program where early activity leads to early recovery. It also has been shown that long periods of rest are harmful and produce adverse changes to tissue biomechanics and morphology. Progressive mechanical loading is more likely to restore strength and to get patients to recover faster. The addition of optimal loading raises new questions on whether this is beneficial or detrimental to the healing process of sprains. The challenge also is defining optimal loading for each individual case for dosage, nature, and timing. Let’s take a look at the evidence to see if optimal loading leads to a better recovery than RICE.

A study by Green, et al. showed looked at passive joint mobilization, a technique commonly used by physical therapists for patients with an acute ankle inversion sprain. Their study included forty-one subjects with acute ankle sprains and they were randomly assigned to two groups: the control group who received RICE and an experimental group that received anteroposterior mobilization along with RICE. At the end of two weeks with treatments every second day, the experimental group required fewer treatment sessions to achieve pain-free dorsiflextion, greater improvement in range of movement, and had a greater increased stride speed. However, a limitation with this study is that the participants followed the RICE protocol at home so the question arises: did the participants actually RICE for as long as they said they did?

Bleakley et al. in another study had two groups with acute ankle sprains, one group had standard treatment (ice and compression) and another group had cryokinetic treatment (ice, compression and exercise consisting of muscle strengthening, neuromuscular training, and sports specific functional exercises five times a week). Function was assessed using the Lower Extremity Functional scale, pain, swelling, and activity levels. Following weeks 1 and 2, the exercise group had a better Lower Extremity Function score and had a higher activity level. The exercise group was also more active as well. They concluded that the aim of initiating early exercise during the acute phase of ankle sprains was to have early reactivation of ankle muscles and movement patterns. For this study as well, the participants wrote in a treatment journal of what they did every day. Again, the question arises, did the participants actually do what they wrote?

Karlsson et al. also completed a study where one group received functional treatment of compression, elevation, early full weight0bearing, and proprioceptive range of motion training. Another group received conventional treatment with compression, protection, and crutches. They also concluded that return to sports activity was higher in the functional treatment group. All three of these studies discuss only certain exercises that they had their participants take, there was not a universal exercise to help with ankle sprains. I think it is interesting that despite having different exercises, they all arrived at the same conclusion. I believe that a study comparing different exercises compared to healing would be interesting to observe.

Overall, all these studies show that some sort of early mobilization helps patients with acute ankle sprains recover faster and have less pain. Despite all the research conducted about early movement, research also lacks on whether ice, compression, and elevation are significant for recovery from sprains as well. With the new burst of research on optimal loading, I am led to believe that optimal loading may be best for a full recovery. However, I also believe that ankle sprains need to be treated differently for each case. For example, an athlete who exercises regularly and uses their ankle more, may be able to have more optimal loading compared to someone who does not exercise regularly. I also believe that more research needs to be conducted to determine which exercises are best for ankle sprains and what these exercises do internally do the muscles. Hopefully, new research will help to show what should be done to heal ankle sprains.

Elevation Training Mask 2.0: “The Swimming Mask”

Posted on February 20, 2017 by mpkraus

As technology advances, physical trainers are constantly seeking new ways to improve their clients training so that they can become the best athletes in sports. A relatively new device, the elevation training mask, has been developed in an attempt to mimic exercise at a high elevation, where the air is thinner and less oxygen is present. Training at high elevations has been shown to cause physical adaptations within the human body to compensate for decreased oxygen levels. Evidence shows that there is an increase in production of red blood cells, which carry oxygen throughout the body, and this increase results in improved efficiency of the body’s utilization of the oxygen present.

In its attempt to simulate these conditions, the elevation training mask has received mixed opinions from doctors, athletes, and trainers. Dr. Teo Mendez, a New York based sports medicine doctor has claimed that the device is actually “unlikely to cause adaptive change, such as an elevation of hemoglobin or blood oxygen carrying capacity.” He claims that this is due to the fact that the air being breathed through the mask still contains the same concentration of oxygen as the air at sea level elevation. On the other hand, the Seattle Seahawks former running back, Marshawn Lynch, used the device during the teams run to Superbowl XLIX. Lynch has praised the device and claims that it has improved his endurance and gives him an extra “boost” when using it to warm up minutes before the game. So why does Lynch praise the device, while Mendez claims that it cannot mimic altitude training effectively? Here’s what the evidence has to say.

In 2016, the Journal of Sports Science and Medicine published a study in which 24 participants completed a six week training program of high-intensity exercise twice a week. The experiment was designed to measure the maximum volume of oxygen a person can use (VO₂max), pulmonary function, ventilatory threshold, and hemoglobin levels before and after training. The results showed that the mask improved the participants’ VO₂max as well as their ventilatory threshold, the point at which oxygen exchange in the lungs is occurring faster that the intake of oxygen, and their power output at this point. However, the mask did not result in any differences in pulmonary function or hemoglobin levels.. In another study, nine participants completed a six week exercise program and the masks were tested as a breathing resistance device. The results of this study showed that the participants’ ventilatory thresholds went up, as well as their maximal voluntary ventilation, which is the maximum volume of air inhaled and exhaled during one minute. Both studies, though, do have several limitations that arise, the biggest one being a small number of participants. This does not allow them to look into differences between genders, age, and physical builds. However, they do show similar results in that the training masks are effective at increasing the user’s ventilatory threshold and voluntary lung capacity increased.

Based on the evidence provided, the elevation training mask has failed its intended purpose. The mask cannot simulate high altitude training and does not result in increased red blood cell production because the air being inhaled contains the same percentage of oxygen as does the air at sea level. However, the mask is effective at improving training and the endurance of its user. The mask adds resistance while breathing that strengthens the user’s diaphragm and other respiratory muscles which lead to the ability to take deeper, fuller breaths. These larger breaths increase VO₂max and push the ventilatory threshold higher as there is more available oxygen to combat the rising exchange rate in the lungs as exercise continues. Essentially, the device mimics the training of swimming, and cause the body build stronger respiratory muscles that allow for larger breaths of air and so more oxygen can be delivered. So while the mask does not fulfill its intended purpose, it is beneficial for endurance training in a similar way to swimming exercises.

Seawater, The Ideal Rehydration Beverage?

Posted on February 20, 2017 by marjelle

You have probably seen the cool commercials showing sweating professional athletes making a legendary play, or training to their maximum level, while drinking their Gatorade or Powerade bottle. Many people, including the brands of these commercially available sport drinks, believe these sport drinks are good for you because they replenish the electrolytes you lose when sweating. However, certain nutritionists and other health and fitness guru’s tell you to stay away from them because they do more harm than good. How does this really work? Do we need to consume these sport drinks when exercising in order to replenish electrolytes?

It is well-known that we sweat during exercise, and that our sweat mainly consist of water and electrolytes. These electrolytes include sodium, potassium, calcium, and magnesium, sodium being the most abundant in our sweat. Sodium is the main cation in extracellular fluid, and its presence has a large effect on plasma osmolality. The amount of sweat and electrolytes lost during exercise varies greatly between individuals, showed by a study done on soccer players. They showed it is affected by factors such as fitness level, sweating rate, and prior diet. For example, sodium concentration in sweat can vary from 20-80 mmol/L. As sodium is the most important electrolyte in our body, it will be the main focus of this review.

Despite the variability within individuals as described above, several studies have researched the effect of sodium concentration in drinks on rehydration during and post exercise. A study published in the European Journal of Applied Physiology found that the addition of sodium to fluids consumed after exercise-induced dehydration has an effect on the rehydration process. More fluid was retained if the sodium concentrations were higher. Subjects did not remain in a positive fluid balance for more than 2 hours when the sodium concentration was low (20 mmol/L). However, drinking fluids with a volume of 1.5 times their sweat loss and a sodium concentration of 60 mmol/L did allow them to remain in a positive fluid balance (meaning that the fluid intake is greater than the fluid output). Another study from University Medical School in Scotland got similar results. They found that in order to sufficiently rehydrate after exercise, both the sodium concentration and volume of the beverage need to be high enough. It is important to note that both of these studies only looked at males, and included a minimum number of subjects. It should also be mentioned that these studies did not take effects of any other components into consideration that are present in many commercially available sports drinks, such as carbohydrates. According to a study about the maintenance of fluid and electrolyte balance during exercise, the total carbohydrate concentrations in drinks consume during exercise should be 5-10%, to avoid delay of fluid and electrolyte absorption. Therefore, sodium concentrations in sport drinks cannot simply be compared to these data in order to determine its efficiency on rehydration.

In addition to drinks, food is also a source of electrolytes. Maughan et al found that urine production was significantly less in subjects that consumed a meal with water after exercise, than in those that had a carbohydrate-electrolyte beverage (sport drink) after exercise. However, they did not give any data on the electrolyte content of the meal and sport drink. Melinda L. et al compared post heat- and exercise-rehydration when consuming chicken broth, soup, sport drinks, and water. They found that plasma volume was not significantly different from predehydration values in the chicken broth and soup trials, but remained significantly below predehydration values for the water and sport drinks trails. Considering the fact that chicken broth and soup had the highest sodium concentrations (109.5 and 333.8 mmol/L respectively versus 0.0 and 16.0 mmol/L in water and sport drinks), this might indicate that higher sodium concentrations have a positive effect on plasma volume recovery. However, it has to be taken into account these four products have large variation in substance (solid/fluid) and electrolytes and carbohydrates composition, so conclusions have to be drawn very carefully.

Analyzing various studies that have been performed on electrolyte and fluid replenishment after exercise, I think it is fair to say that electrolyte composition of fluids consumed after exercise does matter for a successful rehydration process. Looking at the results from University Medical School in Scotland and the article from the European Journal of Applied Physiology, we might be able to say that after intense exercise sport drinks might positively influence the rehydration process, especially compared to water. However, considering the study from Maughan et al and Melina L. et al, I do not think we should say that sport drinks are the ultimate way to rehydrate, as some commercials might suggest. According to this study, subjects remained in positive fluid balance when consuming beverages containing sodium concentrations of 60 mmol/L. This is equivalent to 1379 mg/L, which is not close to the 423 mg/L that for example Gatorade contains. The sodium content of sport drinks is relatively low, while the carbohydrate concentration is relatively high. This makes sense, as a very salty drink most likely does not have a preferable taste. However, if you were to replenish your water and electrolytes purely with sport drinks, you would consume a lot of (unnecessary) sugars. Therefore, I think that consuming sport drinks in order to rehydrate is mostly beneficial during longer training sessions, as the carbohydrates function as a fuel source. However, after exercising I think the calories from the sport drink might counteract the purpose of exercising, and should therefore mostly be consumed after exercise if you don’t have access to food containing high concentrations of sodium. Otherwise, the combination of consuming water and a “salty meal” might be the most efficient way to rehydrate.

Welcome!

Posted on February 1, 2017 by sirooney

Welcome to BMEG467-014: Engineering Exercise, The Blog. Our Spring semester starts February 6, 2017, so you can expect posts to begin populating by February 19, 2017. Until then, we encourage you to visit the other pages to learn more about the course and the blog.

BMEG442: Engineering Exercise and Sports

Applying engineering principles to exercise