My name is Nick and I am currently doing my PhD in physiology with an emphasis in muscle physiology. Welcome to my exercise science blog. Unlike a lot of fitness blogs out there, this one is unique because it is backed by true science. You will find only articles that have been peer reviewed and published in top tier science journals on this blog. For the fast easy read, just read the bold type. If you have any questions do not hesitate to ask me. I am at your disposition for any advice in exercise or just basic physiology. This is not a progress blog to benefit myself but rather to share some of my knowledge and expertise with you that I have gained over my years dedicating my career to exercise science. If I do not know the answer, I will do my best to search through the journals to find it for you. Although I am in biomedical research, I am not a licensed medical professional so please consult a physician before entering any exercise or nutrition program.
Questions?
The most consistent overall finding in endurance and strength-trained athletes who have OTS is a decrease in the maximal lactate concentration while submaximal values are unaffected or only slightly reduced. Glutamine levels are often toted as another possible marker to indicate excessive training stress. However, several problems exist with biochemical testing of overtraining:
Lactate differences can be subtle and depend on the type of exercise test used.
No lactate changes are reported in strength athletes.
Glutamine may decrease with excessive training but low levels are not a consistent finding in OTS.
At first, scientists tried to measure the testosterone/cortisol ratio as a marker of overtraining. This is not possible because this ratio only indicates the actual physiological strain of training. Furthermore, during rest days in endurance-trained athletes, 24 hour cortisol secretion is normal and even comparable to levels of sedentary individuals. Problems exist with hormonal testing as well:
Many factors other than exercise affect blood hormone concentrations such as stress or food intake.
In females, it depends also on the menstrual cycle.
Different hormones are released depending on the modes of training (endurance vs. resistance).
It is noted that there is no definitive way to identify overtraining syndrome (OTS). The only way a coach can do so is by eliminating all other factors that could be causing these symptoms. Once all of the other factors are eliminated, one can then diagnose OTS. The only clear sign is a decrease in performance during competition or training.Currently, there are no simple diagnostic tests to diagnose overtraining and the theories regarding what triggers it are speculative at best.
Taking into account the overlap and still unclear guidelines of overreaching/overtraining, I will now list for you some of the statistics on the prevalence of OTS.
One survey listed a rate of approximately 10% in collegiate swimmers and other endurance athletes.
For elite runners, 60% of females and 64% of males indicated experiencing OTS with numbers being 33% in non-elite adult runners
A recent longitudinal study reported a rate of 29% in age-group swimmers
91% of US collegiate swimmers that reported OTS a first time went on to experience it a second time or more.
To assess OTS, several studies have listed it as being the sum of multiple life stressors, such as training, sleep deprivation, environmental stress, work pressure, and interpersonal problems. Scientists are still looking for a biomaker (in the blood) to measure and determine the existence of OTS.
We know that there must be a balance between appropriate training stress and adequate recovery. Otherwise, this leads to what exercise scientists define as overreaching. Overreaching is an accumulation of training and/or non-training stress resulting in short-term decreases in that capability to perform with or without related physiological and psychological signs and symptoms of maladaptation. Restoration of performance capacity could take several days to several weeks. The difference between this and overtraining is that overtraining is long-term,in which restoration of performance capacity can take several weeks or months. We are looking at solely a time difference between the two.
An example of an athlete who is overreaching would be one that goes to a training camp. The intensity level of the camp is normally very vigorous, which would lead to a temporary decline in performance accompanied later by overall improvement of performance. This can also be noted as functional overreaching. When it gets to the extent of not helping the athlete improve their performance capacity, it then can be described as non-functional overreaching because it leads to stagnation or decreases in performance which will require several weeks or even months to recover.
Overtraining syndrome is considered a syndrome because it takes in to account not just exercise as the main factor but also inadequate nutrition, illness, psychosocial stressors, and sleep disorders.
Below is an example of the difference stages of training and how they relate to overreaching and/or overtraining.
For training to be successful, it must involve an overload on the body but also avoid the negative outcomes of this overload. For the upcoming month up until I leave for the 2013 ACSM conference in Indianapolis (holla atcha boy if you’re going), I will outline for you the mutual American and European “consensus statement” on the Prevention, Diagnosis, and Treatment of Overtraining Syndrome. This will consist of the following sections:
Definitions
Diagnosis
Prevalence
Assessment of overtraining
Biochemistry
Performance testing
Psychology
Physiology
Immune system response
Conclusions
I hope to make clear for you the true scientific evidence on how to diagnosis overtraining and what actually is happening molecularly in the body to bring about these symptoms. If you are a performance coach hoping to better your athletes or someone who wishes to have all the myths surrounding overtraining debunked I promise you the next several posts will be good reads. Until then, all the best!
Are you a girl who regularly skips breakfast? Read on because this well-controlled study is for you.
Introduction: Breakfast skipping is strongly associated with a greater chance of weight gain. Furthermore, this trend is also linked to poorer food choices. Higher protein meals are becoming more popular as a way to improve satiety and appetite control. The purpose of this study was to examine if it is better to skip breakfast or eat one higher in protein in regards to appetite control throughout the remainder of the day.
Methods: Twenty overweight or obese girls between the age of 15-20 who normally skip breakfast were recruited for this study. They were tracked for 7 consecutive days and randomized to one of 3 groups: breakfast skipping (BS), a normal cereal meal for breakfast (NP), or a high-protein breakfast (HP) consisting of beef and eggs for breakfast. Breakfast and lunch were controlled but the rest of the day they were free to eat as much as they wanted.
Results:
NP & HP led to a 60% reduction in daily hunger.
HP lead to a greater increase in total fullness.
NP & HP led to a 30% reduction in daily desire to eat.
HP breakfast but not the others suppressed an important hunger stimulating hormone (ghrelin) by 20%.
HP breakfast but not the others increased an important satiety-stimulating hormone (PYY) by 250%.
BS & NP led to greater evening snacking than HP.
Discussion/Conclusion: A small breakfast of merely 350kcal led to reductions in perceived hunger, the desire to eat, and prospective food consumption. In addition, it also increased fullness. What is even more interesting is that the high-protein breakfast group had additional benefits of a reduction in the hunger-stimulating hormone ghrelin, increases in PYY (a hormone that makes you feel fuller), and decreases in evening snacking, particularly of high-fat foods. The authors note that a limitation of this study was that the breakfast skipping group and the high-protein group had similar total amounts of calories consumed during the day. Although this study looked at 1-week of food consumption, it is not certain if eating a high-protein meal for longer periods of time (a year or more) would prevent weight gain.
My input: The most obvious inferences that the authors draw come from the simple fact that the breakfast skipping group is fasted. Of course, their perceived hunger/fulness, desire to eat, and prospective food consumption will be higher in the morning because they just woke up. I think the most powerful part of the study came from the blood draws and the actual measurable physiological significance that a high-protein breakfast did decrease a hormone responsible for making you want to eat and increase a hormone that tells your brain that you are full.That is what truly stands out as powerful rather than all the other results based solely on questionnaires. For that reason, I’d suggest trying out the high-protein diet over your standard cereal-based breakfast and seeing how it works with your own feelings of satiety throughout the day.
Apologies for the period of dormancy. I’m back and I’m bringing you new articles every Wednesday. With that said, here we go.
Introduction: Men and women store fat on different areas of the body. Women store fat in larger amounts of subcutaneous adipose tissue (the fat under the skin) and men store more visceral fat (the fat around the organs). In general, women have more body fat than men. How much adipose tissue contributes to whole body metabolism is not well known; therefore, this was the aim of the study.
Methods: This was a large cohort coming from hundreds of men and women. The researchers looked at adipose tissue gene expression as well as expression of genes involved in mitochondrial function.
Results:
For the two sexes, fat mass and fat free mass positively correlated with resting metabolic rate (when one went up, the other went up).
Women have a higher metabolic rate per kilogram adipose tissue than men.
Women have a higher expression of genes related to mitochondrial function than men.
Women have a higher number of brown adipocytes in subcutaneous adipose tissue than men.
Discussion: Just to give you an idea of the relative contributions of tissue to basal metabolic rate (BMR), the brain and internal organs account for 70-80% but only make up 5% of the body weight. Skeletal muscle, which everyone in your gym says influences BMR the most, is 20 times lower than the internal organs. Skeletal muscle accounts for about 15% of a person’s BMR. Adipose tissue falls in at around 6% of BMR so we can say it is not that active of a tissue.
From the lab to the gym: So what’s the main takeaway of this study? The practical message is from bullet point 4 of the results and particularly a molecule found in those brown adipocytes known as UCP1. UCP1 is a protein that allows the mitochondria to create heat in the brown adipocytes. Women have a higher amount of UCP1 in their subcutaneous adipose tissue (the fat you want to lose under your skin). Therefore, this study suggests that women have a higher capacity to burn calories by converting energy to heat. Of course the internal organs and muscle are going to contribute the most to your BMR, but the higher metabolic rate of adipose tissue in women gives them an advantage to burn more calories in a resting state than men.
I believe in BCAA’s, particularly leucine for its ability to promote protein synthesis. As far as a performance advantage I believe you’re looking at a 1-3% increase in performance, which is actually around the typical performance increase you get from caffeine ingestion prior to exercise. It doesn’t seem like a lot but if you’re an athlete looking for that small edge that 1% can matter.
gradstudenttiffany-deactivated2 asked: Hey Nick! So happy that I ran across your blog. I myself have a BA in Exercise Science and am currently working on my Masters. There is something that I have been researching on my own for quit awhile as I have been trying to find the best formula for weight loss and more specifically cutting quit a bit of fat weight in the shortest amount of time while preserving muscle. What is your opinion on how much cardio is too much? and what is the best form of cardio in your opinion? HIIT, fasted, LSD
