London sports nutrition uses omega wave i phone app – one way to measure HRV http://www.omegawave.com/professionals
London sports nutrition
Modern day athletes need to take advantage of London sports nutrition and sports science technology to improve their recovery from day to day training loads and maximise subsequent performance. Over reaching and over training are real concerns for many athletes that need to push themselves to the very highest levels. One monitoring tool that has been around for a few years to monitor physiological adaptation to training loads and prevent over training is the use of heart rate variability (HRV). In this article I’m going to briefly discuss what HRV is, how to monitor it and how I modulate it in my London sports nutrition clinic with neutraceuticals to prevent and manage over training. A mentor of mine once quoted to me that there is no such thing as over training, just under-recovery.
London sports nutrition and measuring heart rate variability
HRV is a term that describes the minute differences that occur between each distinct heart beat. If you were to look at an ECG trace of a heart beat it is divided into different periods named P wave, T wave and QRS complex that depict atrial and ventricular contraction and relaxation. Even when the heart is in constant relaxed rhythm there can be minute differences of a few milliseconds between each time the heart beats (measured from one R spike to the next).
When we are rested this HRV occurs as we breathe, with the heart beating slightly faster as we breathe in and beating slightly slower as we breathe out. This variability in heart rate also occurs as we go from lying to sitting or from sitting to standing in conjunction with very slight changes in blood pressure and heart rate to accommodate the oxygen demand of human movement.
The heart rate is controlled by the autonomic nervous system (ANS), with the parasympathetic nervous system (the rest and digest division of the ANS) dominating the heart at rest through its innervation of the sinoartial node (the centre of the heart’s electrical wiring system). As we exercise, the sympathetic nervous system (the fight and flight division of the ANS) that innervates the heart muscle directly increases the speed at which the heart beats to improve delivery of blood and oxygen to working muscles. This activity in the ANS corresponds with anabolic and catabolic hormones – testosterone being anabolic and cortisol being catabolic. After exercise where the heart is stressed and there is less HRV, testosterone drops and cortisol increases, which depicts a post exercise fatigued and catabolic state (see article on testosterone cortisol ratios coming soon…).
As we recover from exercise this balance of anabolic and catabolic hormones shifts back into an anabolic favour, which corresponds to improved HRV. There is some research that demonstrates a correlation between HRV and the testosterone to cortisol ratio in military recruits. Vagal activity (thus PNS activity) decreased the most in recruits that had the lowest T/C ratio suggesting 1) loss of HRV and fatigue, and 2) lower testosterone and higher cortisol. This pointed towards those recruits being in a less adaptive or catabolic state. The authors suggest that long term changes in HRV could be used as a marker for individual anabolic and catabolic balance (Huovinen et al 2009). There is an argument that monitoring HRV could predict when athletes are exposed to injury. For example, if the HRV is poor reflecting sympathetic dominance and poor T/C ratios, the body is in a catabolic state. Cortisol is a catabolic hormone that is capable of breaking down muscle, bone, tendon and ligamentous tissue, potentially weakening them and reducing the amount of stress / strain they can absorb before failure. In theory at least, this could be reflected in “overuse” injuries such as tendopathy or pubic overload.
After periods of prolonged and repetitive bouts of exercise sympathetic nervous system activity on the heart that exceeds momentary metabolic requirements, can remain elevated for some time leading to the signs and symptoms of overtraining. Consider that stress can be defined as increased activation of the sympathetic nervous system and decreased activation of the parasympathetic nervous system. This stress is detected when the heart rate is elevated and HRV is reduced. Therefore recovery can be defined as decreased activation of the sympathetic nervous system and increased activation of the parasympathetic nervous system that can be detected when HR is close to resting levels and HRV is in accordance with breathing rhythm. (Firstbeat Technologies, 2009).
This balance in the autonomic nervous system influence over the heart can be monitored on a daily or weekly basis with technology such as Optima Life or the Omega Wave that measures HRV.
In a state of over training where the heart and nervous system are stressed and maladaptive the heart loses its ability to adapt between each distinct heart beat and beats more like a metronome. This abnormal heart rate variability can also be measured by the aforementioned devices and is seen as a loss in the variability of one R wave to the next on an ECG trace. These devices are a great monitoring tool that i use in my London sports nutrition clinic to assess the physiological adaptation of an athlete to training load (you can but an omega wave app and belt for iphone). If the heart rate variability is good form one session to the next then the athlete can be exposed to another demanding training session, if the heart rate variability is poor training volume needs to be reduced or a recovery day needs to periodised in to their programme.
London sports nutrition supporting HRV
The metabolic system of the heart
The heart, like any other muscle in the body, requires fuel in the form ATP, this ATP needs to be produced from the metabolism of glucose and fatty acids (it is believed that the heart preferentially requires fatty acids for ATP production). First of all carbohydrates undergo glycolysis, a process that metabolises glucose to create molecules of pyruvate. Glycolysis requires vitamins B vitamins, magnesium and manganese as co-factors. Under the presence of oxygen pyruvate passes into the cardiac cells mitochondria where it is converted to acetyl CoA, with the help of vitamin B5. Acetyl CoA then enters the Krebs cycle where it is oxidised to produce ATP and carbon dioxide. This process requires more B vitamins, vitamin C and magnesium and produces electrons that are carried by B vitamin dependent coenzymes to produce a vast amount of ATP via the electron transport chain (ETC). The ETC is a series of electron carrying mitochondrial membrane proteins that requires B2, iron, sulphur, copper and CoQ10 to generate ATP. Of these nutrients CoQ10 is perhaps the most important nutrient for ATP production in the electron transport chain and supplementing this may be necessary. CoQ10 has been shown to supports myocardial infusion, improve diastolic function, left ventricle function and left ventricle wall tension (Houston 2005).
Fatty acids are metabolised differently in the cardiac cells. Carnitine based enzymes are required to transport long chain fatty acids (more than 12 carbons) across the membrane of the mitochondria. These fatty acids then undergo a process called beta oxidation inside the mitochondrial matrix to produce acetyl CoA which then goes in to the Krebs cycle. Carnitine is found in meat, however achieving a therapeutic dose of carnitine is probably only possible with supplements, especially carnitine tartrate. Similarly cartinine is made from lysine that is methylated 3 times, so ensuring adequate B12, B6 folic acid and magnesium in the diet will help carnitine function. In theory at least, improving the hearts ability to produce ATP may improve HRV. Thus providing B vitamins, magnesium and CoQ10 may, in theory, support the metabolic system of heart function and improve HRV, but these nutrients generally do not improve sports performance (Kreider et al, 2010).
The electrical system of the heart
Heart muscle contraction is controlled by action potentials that pass along the nerve axon and along the myocardium via the movement of sodium and potassium across the cell membrane. The action potential then causes the release of calcium within the muscle cell that produces muscle contraction, however it is magnesium, pumped back in to the muscle cell that causes the muscle cell to relax again. Similarly the resting potential within the nerves that control the heart muscle also require magnesium and potassium to promote relaxation. Sodium, potassium and chloride are lost in sweat, therefore hydrating properly after exercise with water and electrolytes is essential of recovery and HRV.
Magnesium is used up for energy production via glycolysis, beta oxidation of fatty acids and in the Krebs cycle, and during muscle contraction. Magnesium is commonly deficient in many athletes as it is used up in the production of ATP and because diets tend to lack an abundance of fish, green leafy vegetables, nuts and seeds. Deficiency in any of these minerals, especially magnesium may lead to poor HRV. Almoznino-Sarafian et al (2009) demonstrated that 300mg of magnesium a day improved HRV in a group of subjects with “normal” magnesium levels. Similarly Brilla et al (2010) demonstrated that 500mg of magnesium supplementation per day enhanced vagal activity and diminished sympathetic activity positively affecting HRV in healthy subjects. We also know that magnesium is essential for cardiovascular health such as managing high blood pressure, arrhythmias and myocardial infarction (Gums 2004 and Houston 2005).
Omega 3 fatty acids are another nutrient that have been shown to positively improve HRV. Ninio, et al (2008) demonstrated 6g a day of fish oil (DHA 1.56 g/d, EPA 0.36 g/d) for 12 weeks improved HRV by increasing parasympathetic activity of the heart.
Summary
Beyond the immune modulating inventions used to help prevent or manage overtraining you can support the metabolic system of the heart with a B complex, carnitine and CoQ10. Supporting the electrical system of the heart by hydrating properly after exercise (refer to hydration article) and by supplementing 300-500mg/d of magnesium (possibly also taurine) and 6g per day of omega 3 may also be very useful.
Refernces
Firstbeat Technologies Ltd, White paper (2009). Heart Beat Based Recovery Analysis for Athletic Training. Accessed online http://www.firstbeat.net/files/white_paper_recovery.pdf
Huovinen, J. Tulppo, M. Nissil , J. Linnamo, V. H kkinen, K. and Kyrolainen, H (2009). Relationship between heart rate variability and the serum testosterone-to-cortisol ratio during military service. European Journal of Sport Science, 9 (5): 277 – 284.
Kreider, R. B. Wilborn, C. D. Taylor, L. Campbell, B. Almada, A. L. Collins, R. Cooke, M. Earnest, C. P. Greenwood, M. Kalman, D. S. Kerksick, C. M. Kleiner, S. M. Leutholtz, B. Lopez, H. Lowery, L. M. Mendel, R. Smith, A. Spano, M. Wildman, R. Willoughby, D. S. Ziegenfuss, T. N. Antonio, J. (2010). Exercise and sport nutrition review: research and recommendations. Journal of the International Society of Sports Nutrition, 7:7
Gums, J. G. (2004). Magnesium in cardiovascular and other disorders. American Journal of Health System Pharmacy, 61(15): 1569 – 1576.
Houston, M. (2005). Nutraceuticals, vitamins, antioxidants, and minerals in the prevention and treatment of hypertension. Progress in Cardiovascular Diseases, 47 (6): 396 – 449.
Almoznino-Sarafian D, Sarafian G, Berman S, Shteinshnaider M, Tzur I, Cohen N, Gorelik O. (2009). Magnesium administration may improve heart rate variability in patients with heart failure. Nutr Metab Cardiovasc Dis. 2009 Nov;19(9):641-5. Epub 2009 Feb 7.
Brilla, L. Teichler, L. Hahn, T. Freeman J. and Li. Y. (2010). Effect of magnesium on heart rate variability in healthy subjects. The Journal of Federation of American Societies for Experimental Biology, 917. 3.
Ninio, D. M. Hill, A. M. Howe, P. R. Buckley, J. D. and Saint, D. A. (2008). Docosahexaenoic acid-rich fish oil improves heart rate variability and heart rate responses to exercise in overweight adults. British Journal of Nutrition. 100 (5):1097 – 103.
London sports nutrition clinic in Wandsworth South West London, call Steve for an appointment.
