July 22, 2013
Overtraining - Conclusion
Over the past month I’ve outlined what exercise scientists consider as “overtraining”.  If you’ve been following these posts you have probably come to the conclusion that overtraining does not exist.  I would have to agree with that due to the lack of clear evidence of support on the topic.  Although I could not put it so elegantly as CT Fletcher, I must admit that the human body does possess a high capacity to adapt to any stimulus that it is given.  An adaptation to training can occur even after one bout of resistance exercise (known as the repeated bout effect).  Most of you spend the majority of your day sitting at sedentary jobs or in classrooms.  To have a truly taxing workout for 1-2 hours per day seems implausible to hinder recovery and performance. The problem is that there are too many variables (nutrition, sleep, mood, etc) to consider to even have a well-controlled study on overtraining.  Of course, you must have proper rest and adequate nutrients to continue performing at a certain level.  Lacking those two variables alone could be the culprit in the decrements you see with training and not the actual training itself.  The best available source for coaches to try to diagnose overtraining is in this checklist provided by the ACSM review.  I hope that you were able to take away the recent standpoint on overtraining in the scientific community and understand the lack of concise and consistent data in support of it.

Overtraining - Conclusion


Over the past month I’ve outlined what exercise scientists consider as “overtraining”.  If you’ve been following these posts you have probably come to the conclusion that overtraining does not exist.  I would have to agree with that due to the lack of clear evidence of support on the topic.  Although I could not put it so elegantly as CT Fletcher, I must admit that the human body does possess a high capacity to adapt to any stimulus that it is given.  An adaptation to training can occur even after one bout of resistance exercise (known as the repeated bout effect).  Most of you spend the majority of your day sitting at sedentary jobs or in classrooms.  To have a truly taxing workout for 1-2 hours per day seems implausible to hinder recovery and performance. The problem is that there are too many variables (nutrition, sleep, mood, etc) to consider to even have a well-controlled study on overtraining.  Of course, you must have proper rest and adequate nutrients to continue performing at a certain level.  Lacking those two variables alone could be the culprit in the decrements you see with training and not the actual training itself.  The best available source for coaches to try to diagnose overtraining is in this checklist provided by the ACSM review.  I hope that you were able to take away the recent standpoint on overtraining in the scientific community and understand the lack of concise and consistent data in support of it.

June 26, 2013
Dietary Supplements for Strength & Power Athletes

The following was presented by Eric Rawson at the 2013 ACSM Conference.  It is my pleasure to share it with you.

1.) Creatine monohydrate 

Doses: 0.3 g/kg/day for 5 days or 0.03 g/kg/day for 30 days is sufficient to increase the concentration of creatine by 20-25%.  

Washout period: 6 weeks is usually recommended

Performance factor: Increase performance of high intensity exercise of durations less than 30 seconds

Safety profile: Excellent

2.) Beta-alanine

Doses: 3-6g for 4-8 weeks can elicit 40-50% increases.  Acts as a buffer

Washout period: 10-15 weeks

Performance factor: Good for H.I.I.T. or sprinting. High intensity exercise (1-6min duration).  Overall 2.58% increase in performance

Safety profile: Safe but may cause a niacin flush (paresthesia)

3.) Sodium Bicarbonate (NaHCO3)

Doses: 300mg/kg taken 1-3 hours pre-exercise can act as an extracellular buffer

 Washout period: None.  Some suggest as a chronic dietary supplement.

Performance factor: 1-2% increase in body mass.  Increase in high intensity exercise (1-5min). Shown previously to take 0.8s off of a 1 min race.  

4.) Protein

Dose: 0.4 g/kg/hour of exercise (Milk is the best bang for your buck)  1.6-1.7 g/kg/day. 

5.) Water

I think it also important to not neglect your carbohydrates.  In exercises lasting 30 seconds to 1 minute, a lot of people think that most of the energy is coming from creatine.  In actuality, 10% is coming from creatine whereas 47-60% is coming from carbohydrate stores.  1.2 g/kg/hour of carbohydrates post-exercise is sufficient for muscle glycogen resynthesis. 

June 12, 2013
Overtraining - Physiology & Immune System

Several physiological factors have been proposed that could relate to overtraining syndrome.  It seems the most plausible one is a reduced maximal heart rate but studies suggest this is not a valid tool to measure OTS due to inconsistent results.

Sustained periods of intense training leads to decreases in innate and adaptive immunity.  Depressed immunity typically is said to occur for athletes at the end of the season or during the most intensive periods of their training.  The only evidence that exists for a decrease in immune function in athletes experiencing OTS is anecdotal.

In regards to resistance training, when excessive volumes of max loads are used, maximal muscular strength is one of the last performance measures to be negatively affected.  Rather, high speed (ie. sprinting) and power are the first types of performance to be affected.

There is no evidence that OTS can be treated.  Rest and very light training seem to be the only agents capable of effecting recovery.  It is generally recommended that athletes should have one passive rest day each week.  Trying to prescribe an exact amount of hours of sleep per night is difficult.  Therefore, a good starting point is to advise athletes to sleep for the amount of time required to feel wakeful during the day.

May 15, 2013
Overtraining - Biochemistry & Hormones

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).
  • Diurnal and seasonal variations of hormones.

May 8, 2013
Overtraining - Diagnosis, Prevalence, & Assessment

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.

May 1, 2013
Overtraining - Definition

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.

April 24, 2013
Joint Consensus Statement of the European College of Sport Science & the American College of Sports Medicine on Overtraining Syndrome

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!

Nick

January 31, 2013
Mythbusting obesity and some actual facts.

A fresh article was published in the New England Journal of Medicine yesterday that looks at the most common myths, presumptions, and facts about obesity.  What really makes this paper intriguing is that the authors used internet searches to find these.  Since some of you might not have assess to the full text, or not have the time to read the entire article, I’ll highlight some of them for you below.

The myths (the authors define myths as “beliefs held true despite substantial evidence refuting them”)

  • Small sustained changes in energy intake or expenditure will produce more substantial long-term weight changes.
  • Setting realistic goals for weight loss is important; otherwise, people will become frustrated and likely lose less weight.
  • Slower gradual weight loss is better than large rapid weight loss in regards to long-term outcomes.
  • PE classes in school play an important role in reducing or preventing childhood obesity.
  • A bout of sexual activity burns 100-300 kcal for each participant. (The authors state the actual numbers are more like 14-21 kcal considering the average sexual experience lasts 6 minutes, ouch).

The presumptions (the authors define presumptions as “unproved yet commonly espoused propositions”)

  • Eating breakfast each day as opposed to skipping it is protective against obesity.
  • Eating more fruits and vegetables will result in weight loss or less weight gain, regardless of any other behavioral or environmental modifications.
  • Weight cycling (yo-yo dieting), is associated with increased mortality.
  • Snacking contributes to weight gain and obesity.
  • An individual’s environment (parks, recreational playgrounds, etc.) influence the incidence and prevalence of obesity.

THE FACTS (“sufficient evidence to be considered empirically proved”)

November 28, 2012
Nighttime snacking reduces whole body fat oxidation and increases LDL cholesterol in healthy young women.

This one is for the night-eaters. The ones who find themselves diving into some snacks before bed.  You know who you are.  Did you know they actually consider this a syndrome though?

Introduction:  Night eating syndrome is classified as a delay in the circadian timing for food intake which can alter metabolism and eventually lead to obesity.  This syndrome is diagnosed as ingesting a quarter of your total energy for the day after an evening meal up to three times per week.  The aim of this study was to see how two weeks of snacking either during the day or at night, without changing meal frequency, would alter energy metabolism in lean young women.

Methods:  13 lean healthy women were recruited with 7 of them being randomly assigned to the snacking during the day group (10:00am) and the other 6 to the snacking at night group (11:00pm).  After the two weeks, their energy expenditure and substrate utilization were measured in a whole-room respiratory chamber for one day.  The snack consisted of merely 200kcal.  Breakfast, lunch, and dinner were given at 9:00am, 2:00pm, and 7:00pm for each group during the two weeks.

Results:

During the afternoon, the group that snacked at night had a significantly higher RQ (using more carbohydrates instead of lipids for energy) and significantly lower fat oxidation.  There was a small decrease in 24-hour fat oxidation with the group that snacked at night but this was not statistically significant.  LDL cholesterol levels significantly increased as well in the group that snacked at night.

My input:  A major strength of this study was the strict control of meal frequency during the two weeks.  However, the groups were small and likely underpowered when it came to statistical significance, particularly with the slight decrease in 24-hour fat oxidation which could have been significant had they recruited more volunteers.  Regardless, this study shows the importance of nutrient timing and how eating at specific hours of the day can alter our metabolism due to the hormones naturally controlled by circadian rhythms at those hours.  It is a necessity for the nutritional science field to step away from calories in versus calories out and start looking more towards nutrient timing at different hours of the day under different conditions (rest versus pre/post-exercise).

Hibi et al Am J Physiol Regul Integr Comp Physiol. 2012 Nov 21

October 12, 2012
Effects of Dehydration during Cycling on Skeletal Muscle Metabolism in Females

Exercising in a dehydrated state can hurt performance.  That really is nothing new.  However, what is not known is how dehydration can effect substrates being used by the  muscle during exercise, particularly in women.  So, this one is for you ladies.

Introduction:  Did you know that a 2% loss in body mass because of dehydration can elevate HR, core temperature, and the osmolarity of blood plasma?  Did you also know that it is said that women thermoregulate less effectively because of a higher core temperature during the same exercise load as men?  In fact, females usually experience a quicker rise in core temperature during exercise.  Depending on core temperature during exercise, the body can switch between using muscle glycogen or fat.  Therefore, you could say that depending on hydration status (which effects core temperature) the body will switch between these two fuel sources as well.  But which one?  The hypothesis in this study states that women will rely more heavily on whole body carbohydrate oxidation as well as the breakdown of glycogen from muscle during dehydrated exercise.

Methods:  Nine women underwent cycling at 65% VO2peak for 120 min.  Some received fluids during the exercise and the others did not.  It is important to note that before the exercise trial, both groups were properly hydrated.  Thus, this study is just examining the consequences of not drinking water during prolonged endurance exercise.

Results: One way to measure whether or not you are using carbohydrates or fat during exercise is by a method called indirect calorimetry, which can provide you with a RER.  RER, as I’ve described before, is the respiratory exchange ratio.  A RER of 1 means you are using primarily carbohydrates and a RER closer to 0.75 means you are using primarily fat.  With that said, the RER of the dehydrated group was significantly higher than the hydrated group, meaning that they were using more carbohydrates during exercise.  Likewise, carbohydrate oxidation and total body carbohydrate oxidation was higher in the dehydrated group whereas fat oxidation was lower.  The dehydrated group had a significantly higher core temperature and heart rate as well.

Discussion:  At this point you would probably like to know why being dehydrated makes the body rely more on carbohydrates rather than fat.  There currently is no answer to that; however, the authors suggest three theories behind it.

  1. An augmented nervous system response from the adrenal glands leading to activation of an enzyme that uses glycogen.
  2. Low energy levels that are sensed in cells
  3. Higher intramuscular temperature (which appears to be the primary mechanism)

My input:  It is now being understood a little more why dehydration causes performance deficits.  Clearly, if you are going to tap into your muscle glycogen faster, you will not be able to perform as long as if you were using primarily fat, which is very energy rich.  Still, more needs to be done to understand the exact mechanism for the switch.

Logan-Sprenger et al Med Sci Sports Exerc. 2012 Oct;44(10):1949-57.