Introduction

How much aerobic exercise is too much?  What must first be defined is your target population. The answer will differ according to the demographic.  For example, the answer to that question would look very different for a pregnant person compared to someone preparing for a triathlon.  The answer will also vary if you were addressing the needs of an American football player during pre-season compared to someone diagnosed with an immune disorder.

Since 490 BC people have been running marathons (Mohseni et al., 2011).  Personally, I have trained several people competing in marathons.  In light of that and the fact that over 400,000 people in the United States alone will compete in a marathon this year I have chosen to focus my efforts on marathon runners (Fortescue et al., 2007).

One way to frame the question could be, “Are the cardiovascular (CV) and other physiological effects of running a marathon more harmful than helpful?”  We all know aerobic exercise is good for the body but is running 26.2 miles more than the body can safely adapt too?

Marathon Running

Aerobic exercise has been proven to enhance the function of the CV system (Dawson et al., 2008).  But is there a point of diminishing returns?  Troponin I (CTnI) is a serum marker used to indicate cardiac damage.  Clinical levels of CTnI ≥ 0.50 ng/mL results in an acute myocardial infarction (AMI) diagnosis (Fortescue et al., 2007).  AMI is also knows as a heart attack. In a study examining 17 recreational runners 11 of these had statistically significant increased levels of CTnI above the threshold for an AMI diagnosis six hours post-marathon completion (O’Hanlon et al., 2010).  (Dawson et al., 2008) following 13 runners during the 2007 London Marathon observed that seven of these had CTnI levels above the AMI cut-off.  In a study designed to identify the characteristics of a runner more predisposed to elevated troponin levels 55 of the 482 (11%) runners evaluated in the 2002 Boston Marathon had troponin levels above the AMI threshold.  This study measured both Troponin T and Troponin I (Fortescue et al., 2007).  In relation to the study’s purpose it was concluded that younger runners (≤ 30 years) and those with less marathon experience (≤5) were more likely to have increased troponin levels.

Cardiovascular changes were not the only changes noted.

Mohseni (2011) monitoring 195 marathon and half-marathon participants observed that there was a statistically significant increase in blood urea nitrogen (BUN) levels that clinically would be classified as renal dysfunction.  45.8% of the 83 runners with increased BUN levels would be considered to have moderate to severe renal dysfunction.  According to his data he also found men participating in the marathon to be 9x as likely to develop levels classified as moderate renal dysfunction.  Vascular function was also discovered to be at risk. Dawson (2008) found a clinically significant decrease in the femoral artery flow-mediated dilation (FMD) response compared to that of the brachial artery.

 Conclusion

The findings above indicate CV, renal, and vascular changes to be of concern.  However, the clinical significance of these changes is not yet known.  More studies need to be conducted and in particular more longitudinal studies.  One question to ponder in relation to the cardiac response is- Are the changes pathological in nature or physiological and transient which would lead to enhanced cardiac muscle and function?  Other differences that may influence study outcomes include but are not limited to gender, age, the effects of altitude, marathon completion time, and recreational vs. elite athlete.

References

Dawson, E. A., Whyte, G. P., Black, M. A., Jones, H., Hopkins, N., Oxborough, D., Gaze, D., Shave, R. E., Wilson, M., George, K. P., &  Green, D. J. (2008). Changes in vascular and cardiac function after prolonged strenuous exercise in humans. Journal Of Applied  Physiology, 105(5), 1562-1568.

Fortescue, E., Shin, A., Greenes, D., Mannix, R., Agarwal, S., Feldman, B., Shah, M. I., Rifal, N., Landzberg, M. J., Newburger, J. W., & Almond, C. (2007). Cardiac troponin increases among runners in the Boston Marathon. Annals Of Emergency Medicine, 49(2), 137-143.

Mohseni, M., Silvers, S., McNeil, R., Diehl, N., Vadeboncoeur, T., Taylor, W., Shapiro, S., Roth, J., & Mahoney, S. (2011). Prevalence of Hyponatremia, Renal Dysfunction, and Other Electrolyte Abnormalities Among Runners Before and After Completing a Marathon or Half Marathon. Sports Health: A Multidisciplinary Approach, 3(2), 145-151.

O’Hanlon, R., Wilson, M., Wage, R., Smith, G., Alpendurada, F. D., Wong, J., Dahl, A., Oxborough, D., Godfrey, R., Sharma, S., Roughton, M., George, K., Pennell, D. J., Whyte, G. & Prasad, S. K. (2010). Troponin release following endurance exercise: is inflammation the cause? a cardiovascular magnetic resonance study. Journal Of Cardiovascular Magnetic Resonance, January 2010;12:38-44.

Introduction

The physiological benefits of exercise have been addressed by many of my cohorts. I read and reread the discussion question several times, trying to determine what, specifically, we were being asked to answer.  Finally, the phrase hit me: “Enhance their quality of life.”

As suggested by colleagues, various forms of exercise can help reduce or control risk factors associated with disease and illness.  Many of the physiological benefits of exercise are used as treatment or management of events that will occur in the future.  For example, it is well known that resistance training and cardiovascular exercise have been shown to help control risk factors such as hypertension, obesity and diabetes that may help reduce the risk of cardiovascular disease (CVD) — an event of the future.  Resistance training has also been shown to increase bone mass density (BMD), which may help manage the future onset of osteoporosis.

For these reasons, I have chosen to research the current literature for a mode of exercise that has the potential to enhance the quality of life of its participants immediately.  As stated, this is somewhat of an unrealistic assignment as one would seldom, if ever, recommend only one mode of exercise.  An integrated approach is the preferred method for optimal health.  I have chosen cardiovascular exercise as the preferred mode of exercise for a healthy, young adult (late 20s-early 30s) to potentially enhance their quality of life, and resistance training for healthy adults age 60+.

Adults (late 20s-early 30s)

Cardiovascular exercise is my chosen mode of exercise for this group because of proven data to support its ability to enhance quality of life.  One of the things unique to improving this group’s present quality of life is the fact that the benefits are immediate.   Some of the physiological benefits take weeks to appear.  A study (Rokka, Mavridis, & Kouli, 2010) of 136 men and women with a mean age of 28.5 showed statistically significant decreases in anxiety/tension, depression, confusion, and aggressiveness with increased energy in a single, 60-minute cardiovascular session.

Another unique characteristic to cardiovascular exercise and its potential to enhance the quality of life is the possibility that the weekly frequency and duration may be less than that needed to obtain physiological benefits. This may lead to an increased adherence.  Another study (Annesi, 2003) of 104 men and women with a mean age of 32.6 found that participants who performed cardiovascular exercise for as little as 15 minutes per day, two or three times per week, had statistically significant decreases in depression and tension.

Adults (60+)

Resistance training is my chosen mode of exercise for adults age 60+.  In addition to the large amount of research suggesting resistance training’s vast physiological effects for this population, there is also literature extolling its functional quality of life benefits.  In a study (Bates et al., 2009) using the SF-36 Health Survey, 110 men and women with a mean age of 68.2 who engaged in a resistance training program were found to have statistically significant increases in physical functioning, including activities of daily living (ADL) such as bathing and dressing. In addition, they showed an increased vitality or energy level.

Another study examining participants between the ages of 65-72 suggested that resistance training resulted in a sense of autonomy and competency in performing activities such as walking and biking, along with ADL such as getting in and out of a bath and/or bed (Dionigi & Cannon, 2009).

Conclusion

According to the peer-reviewed literature above, I recommend cardiovascular exercise as the mode of exercise for adults in their late 20s-early 30s to enhance their quality of life.  For adults 60+ I recommend resistance training.  As I alluded to earlier, these quality of life benefits can be seen immediately and might require less frequency and duration than exercise seeking physiological changes. Therefore, an increased adherence.

I think further investigation of these issues would be a fruitful means to helping more people enhance their current quality of life.

References

Annesi, J. J. (2003). Effects of cardiovascular exercise frequency and duration on depression and tension changes over 10 weeks. European Journal Of Sport Science, 3(4),1-12.

Bates, A., Donaldson, A., Lloyd, B., Castell, S., Krolik, P., & Coleman, R. (2009). Staying active, staying strong: pilot evaluation of a once-weekly, community-based strength training program for older adults. Health Promotion Journal Of Australia, 20(1), 42-47.

Dionigi, R. A., & Cannon, J. (2009). Older adults’ perceived changes in physical self-worth associated with resistance training. Research Quarterly For Exercise & Sport, 80(2), 269- 280.

Rokka, S., Mavridis, G., & Kouli, O. (2010). The impact of exercise intensity on mood state of participants in dance aerobics programs. Studies In Physical Culture & Tourism, 17(3), 241- 245.

Introduction

Starbucks.  Rockstar.  Mountain Dew.  All names synonymous with caffeine but can they really help you during exercise? The most agreed upon hypothesis is that caffeine attaches to adenosine receptors and this mitigates adenosine’s role as an inhibitor of the Central Nervous System (CNS) specifically neuro-excitability, neurotransmitter release and arousal (1,2,4).  Since 2004 when caffeine was removed from the World Anti-Doping Agency  list of banned substances its use as an ergogenic aid in sport has become widespread (2,4).  Although much has been written about caffeine’s effect on endurance athletes and pregnant women this paper does not explore these populations.  My purpose was to research the neural benefits and health risk factors for a healthy individual consuming a moderate amount of caffeine (300mg/day) who is physically active for general health and wellness reasons.

Neural Benefits

My discoveries were less than impressive for the general population and the use of caffeine as an aid for their daily exercise performance.  One study that administered 6/kg of caffeine found that despite increased energy expenditure there were no significant changes in heart rate, rate of perceived exertion (RPE), respiratory exchange ratio (RER), or total work done (4).  Another study comparing older woman (50-67 years) with younger women (18-22 years) who consumed an average of 240mg of caffeine for the study showed no significant change in heart rate for either group (1).  But subjective states of
depression decreased for the older women while there was an increase in vigor and tension with a decrease in fatigue for the younger group.  Crowe testing the anaerobic effects of caffeine using two, 60 second max effort bouts of cycling did not find a significant change in RPE or total work achieved or any significant changes in reaction time or number recall (2).

Risk Factors

Crowe using a dosage of 6mg/kg had two participants out of 17 experience short term side effects that included hand tremors, feelings of hyperactivity, restlessness, agitation, dizziness and nausea (2).  Arciero found significant increases in the older women’s systolic and diastolic blood pressure while only the diastolic blood pressure increased in the younger women (1).  Scher’s abstract revealed limited evidence to suggest that caffeine was linked to chronic daily headaches (3).  Although the purpose of this paper was to research physically healthy individuals one thing I regularly see in my personal training intake questionnaires is the use of prescribed anti-anxiety and antidepressant medications.  One study examining heart rate variability before and after exercise using 5mg/kg caffeine found increased heart rate variability at rest before exercise and more importantly an increase in high frequency power (5).  The authors expressed concern for caffeine users who suffer from anxiety and depression.

Conclusion

Given the current research I see little benefit for a healthy non-caffeine consumer to start using caffeine as an exercise enhancement tool.  Nor do I see reason for great concern for the client who is already a moderate caffeine consumer unless they already suffer from anxiety and/or depression or range in age from 50-67 and suffer from high blood pressure.  One thing that I think should be taken into account is the relative versus absolute caffeine dosage.  Most people think of caffeine use in grams per day.  For example, two cups of coffee equals approximately 250-275g of caffeine.  That 275g may affect a 110lb female much differently than a 250lb male.  Also, the studies varied on how the caffeine was administered so I would be interested in reading more on the effects of caffeine being taking in pill form versus food form such as found in coffee or Rockstar.

References

1.  Arciero P, Ormsbee M. Relationship of blood pressure, behavioral mood state, and physical activity following caffeine ingestion in younger and older women. Applied Physiology, Nutrition & Metabolism. August 2009;34(4):754-762.

2.  Crowe M, Leicht A, Spinks W. Physiological and cognitive responses to caffeine during repeated, high-intensity exercise. International Journal Of Sport Nutrition & Exercise Metabolism. October 2006;16(5):528-544.

3.  Scher A, Stewart W, Lipton R. Caffeine as a risk factor for chronic daily headache: A population-based study. Neurology. December 2004;63(11):2022-2027.  Abstract only used.

4.  Wallman K, Goh J, Guelfi K. Effects of caffeine on exercise performance in sedentary females. Journal Of Sports Science & Medicine. June 2010;9(2):183-189.

5.  Yeragani V, Krishnan S, Engels H, Gretebeck R. Effects of caffeine on linear and nonlinear measures of heart rate variability before and after exercise. Depression And Anxiety. 2005;21(3):130-134.

Creatine is largely accepted as an ergogenic aid in activities of short duration (less than 30 seconds) and of high intensity (2,3).  In these studies activities such as 1RM bench press, 1RM leg press and anaerobic running capacity have seen significant increases.  The human body utilizes three different energy systems when supplying energy for muscular contractions.  They are the adenosine triphosphate-phosphocreatine (ATP-PC), glycolysis and the oxidative phosphorylation systems.  The use of a creatine supplement has been proven to increase the creatine stores in the muscle fibers which allows for faster ATP production via the ATP-PC system (2,3). Research indicates a safe dosage consists of a 20g/day loading phase for 5-7 days with these daily doses being broken down into 5g ingested four times per day followed by a maintenance phase of 3-5g/day (1).

Health Risks

One concern with any nutritional supplement is the possibility of long-term and short-term health risks.  Anecdotal evidence has linked creatine use to short-term health concerns such as Gastrointestinal (GI) Distress which can include vomiting and diarrhea and more serious long- term concerns such as muscle, liver and kidney damage.  My review of the literature finds nothing to date that scientifically supports damage to the muscle, liver or kidneys (1,4,5). One study followed professional basketball players for three seasons, measuring various muscle, liver and kidney blood markers and found no significant outliers (5).  Although the literature does not suggest GI distress to be of concern, one study did find that a dose of 10g/day consumed all at once caused slightly more GI distress in the form of diarrhea than those participants who took 10g/day but the 10g was broken into two doses of 5g taken 12 hours apart (4). But as mentioned in the introduction, 10g/day falls outside of the accepted healthy range of 5g/day (3,4).

Performance Enhancer or Diminisher?

As stated above, creatine supplementation aids the ATP-PC energy system and has been proven to benefit activities that are of high intensity and short duration, lasting 30 seconds or less (2,3).  Activities such as football, short running and cycling sprints and weightlifting are just a few.  Activities of longer durations that rely on the oxidative phosphorylation energy system have not been proven to benefit from a creatine supplement (3). There is conflicting evidence whether creatine  causes an increase in bodyweight (2,3).  This may be of concern if your activity is weight sensitive and one or two pounds of
bodyweight can have a detrimental effect on the outcome of your performance. There  is also conflicting evidence about whether men and women benefit equally.  One study showed that men’s anaerobic running  capacity increased but the women participants’ did not (2).

Conclusion

The current research findings suggest the use of a creatine supplement to be safe and effective for healthy individuals participating in activities that require short burst of muscular strength and power.

References

1.  Bemben, M.G., & Lamont, H. S. (2005). Creatine Supplementation and Exercise Performance: Recent Findings. Sports Medicine, 35(2), 107-125.

2.  Fukuda, D.H., Smith, A. E., Kendall, K. L., Dwyer, T. R., Kerksick, C. M., Beck, T. W.,Cramer, J.T., Stout, J. R. (2010). The Effects Of Creatine Loading And Gender On Anaerobic Running Capacity. Journal Of Strength & Conditioning  Research (Lippincott Williams & Wilkins), 24(7), 1826-1833.

3.  Herda, T.J., Beck, T. W., Ryan, E. D., Smith, A. E., Walter, A. A., Hartman, M. J., Stout, J.R., Cramer, J. T. (2009). Effects Of Creatine Monohydrate And Polyethylene Glycosylated Creatine Supplementation On Muscular Strength, Endurance,  And  Power Output. Journal Of Strength & Conditioning Research (Lippincott Williams & Wilkins), 23(3), 818-826.

4.  Ostojic, S. M., & Ahmetovic, Z. (2008). Gastrointestinal Distress After Creatine Supplementation in Athletes: Are Side Effects Dose Dependent? Research In Sports Medicine, 16(1), 15-22.

5.  Schröder, H., Terrados, N., & Tramullas, A. (2005). Risk Assessment Of The Potential Side Effects Of Long-Term Creatine Supplementation In Team Sport Athletes. European Journal Of Nutrition, 44(4), 255-261.

Disclaimer:  This posting does not include my recommendation to use creatine or my endorsement for any brand or manufacturer.

The Human Movement System (HMS) is a beautiful yet intricate system.  In layman’s terms when the HMS is functioning optimally the body is said to be  firing on all cylinders.  When there is dysfunction in the HMS, body parts start to wear out and break down.  But what exactly is the HMS?  The HMS is the skeletal, nervous, and muscular systems working interdependently to produce optimal neuromuscular control.  In order for optimal neuromuscular control to  be achieved the body must start in an ideal posture state.  When the body is properly aligned there are normal length-tension relationships, force couples and joint arthrokinematics.  The muscle has an optimal length that allows it to produce the most tension.  This is termed the length-tension relationship.  When the optimal length-tension is disrupted there is dysfunction which can result in reciprocal inhibition.  As noted the muscles function interdependently of each other.  The agonist may produce the prime movement but it is also the work of the antagonist, synergists and stabilizers that allow the entire movement to  happen.  It is the synergy of all the muscles and their independent actions that provide for an unhindered force couple.  If this force couple is disrupted  it will result in synergistic dominance where the synergists and stabilizers will take over for the prime movers, hence, doing a task they were never designed to do and increasing the risk of injury.  The joints also have an optimal range of motion.  When these normal ranges of motion are disrupted joint arthrokinetic inhibition can occur affecting the muscles surrounding the joint.  When the HMS is functioning optimally there is optimal sensorimotor integration,  neuromuscular efficiency and tissue recovery.  When the system is disrupted there is altered sensorimotor integration, neuromuscular efficiency and tissue fatigue and break down.

Often the first thing that presents itself is the symptom of a dysfunction in the HMS.  As health professionals I want us to start looking past the symptom to identify and address the cause.  This is very applicable from the client who has back pain to the soccer player with Iliotibial Band Syndrome (ITBS).  What problems may arise from poor posture?  If an athlete has a weak hamstring what are the parts of the HMS that may be altered?  We must ask ourselves where in the kinetic chain is the problem occurring?

The Trickle Down Effect

The most common lateral, overuse injury in runners is ITBS (Falvey et al., 2010; Grau, Maiwald, Krauss, Axmann & Horstmann, 2008).  The Iliotibial Band (ITB) is a thick fibrous tissue that runs from the Tensae Fasciae Latae (TFL) to the lateral femoral epicondyle. Patients and/or athletes will usually complain of a lateral knee pain.  At first glance one may think that the problem is isolated to the lateral, distal part of the femur.  But as was discovered earlier the HMS functions as an interdependent system.  The laymen train of thought would be that ITBS must be caused by a tightITB.  Therefore, stretch the ITB and this should solve the problem.  The professional says let’s look at the whole kinetic chain.  Devan, Pescatello, Faghri & Anderson (2004) studied 53 NCAA Division 1 female athletes and found that a tight ITB did not lead to ITBS but a decreased Hamstring to Quadriceps ratio (H:Q), as well as, genu recurvatum increased the athlete’s risk to overuse injuries at the knee.  Another study linked ITBS to decreased hip adduction, less internal and more external rotation of the tibia and less eversion at the subtalar joint (Grau et al., 2008).  Findings such as these mentioned above and understanding the dynamic relationship of the HMS can also help the athletic trainer and/or physical therapist when diagnosing and treating injuries.  A study by (Falvey et al., 2010) on 20 human cadaver ITBs suggested that the treatment should be directed at lengthening the TFL and gluteus maximus rather than the ITB.  Fredericson & Wolf (2005) mentioned another example of treating a part of the kinetic chain not necessarily near the presenting problem.  They suggested that a tight gastrocnemius and soleus leads to decreased dorsiflexion leading to increased ankle pronation and knee flexion, hence, increasing the risk of ITBS.

Conclusion

For optimal function of the human body an interrelated muscular, nervous, and skeletal system termed the Human Movement System must be viewed in its entirety.  As a health professional we should ask ourselves- What is the cause of the problem not just focus on the symptom or presenting problem.

References

Devan, M. R., Pescatello, L. S., Faghri, P. P., & Anderson, J. J. (2004). A prospective study of overuse knee injuries among female athletes with muscle imbalances and structural abnormalities. Journal Of Athletic Training, 39(3), 263-267.

Falvey, E. C., Clark, R. A., Franklyn-Miller, A. A., Bryant, A. L., Briggs, C. C., & McCrory, P. R. (2010). Iliotibial band syndrome: an examination of the evidence behind a number of treatment options. Scandinavian Journal Of Medicine & Science In Sports, 20(4), 580-587.

Fredericson, M., & Wolf, C. (2005). Iliotibial band syndrome in runners: innovations in treatment. Sports Medicine, 35(5), 451-459.

Grau, S., Maiwald, C., Krauss, I., Axmann, D., & Horstmann, T. (2008). The influence of matching populations on kinematic and kinetic variables in runners with iliotibial band syndrome. Research Quarterly For Exercise & Sport, 79(4), 450-457.

Written by PJ Musilli CSCS

“The body is the storehouse of the emotional pain of early life as well as the consequences of trying to deal with that pain through coping mechanisms such as repression and compensatory activity…Emotions are energy.”

Yes, we must exercise and eat well to maintain our bodies.  And, the body has other needs as well.