Wednesday, January 28, 2009

Is heart rate a convenient tool to monitor over-reaching? A systematic review of the literature.

Keeping you up to date on the cutting edge of research, we march on.

Here is a great review on the use of heart rate to monitor performance. This study was looking at over-reaching. The literal definition of over-reaching is " To miss by reaching too far or attempting too much" While some athletes may use this to push their body in order to allow for super compensation (an increase in performance after a period of hard training) , too much pushing and an over reaching state can turn into over training syndrome (OTS).

While OTS is rare, if you hit it you are down and out for MONTHS! Again, while rare, it can happen in elite athletes. If you are only exercising 5 hours a week, you don't have to worry about OTS so get to the gym! Even elite athletes that exercise for many hours a week will never reach an OTS state.

Keep in mind that this is a meta analysis (pooling of studies) and this was done in ELITE athletes. There are also many ways to determine heart rate variability (HRV).

Is heart rate a convenient tool to monitor over-reaching? A systematic review of the literature.

Bosquet L, Merkari S, Arvisais D, Aubert AE. Département de Kinésiologie, Université de Montréal, CP 6128, Succursale Centre Ville, Montreal, Quebec, Canada H3C 3J7.

OBJECTIVE: A meta-analysis was conducted on the effect of overload training on resting HR, submaximal and maximal exercise HR (HR), and heart rate variability (HRV), to determine whether these measures can be used as valid markers of over-reaching.

METHODS: Six databases were searched using relevant terms and strategies. Criteria for study inclusion were: participants had to be competitive athletes, an increased training load intervention had to be used, and all necessary data to calculate effect sizes had to be available. An arbitrary limit of 2 weeks was chosen to make the distinction between short-term and long-term interventions. Dependent variables were HR and HRV (during supine rest). Standardised mean differences (SMD) in HR or HRV before and after interventions were calculated, and weighted according to the within-group heterogeneity to develop an overall effect.

RESULTS: In these competitive athletes, short-term interventions resulted in a moderate increase in both resting HR (SMD = 0.55; p = 0.01) and low frequency/high frequency ratio (SMD = 0.52; p = 0.02), and a moderate decrease in maximal HR (SMD = -0.75; p = 0.01). Long-term interventions resulted in a small decrease in HR during submaximal (SMD = -0.38; p = 0.006) and maximal exercise (SMD = -0.33; p = 0.007), without alteration of resting values.

CONCLUSION: The small to moderate amplitude of these alterations limits their clinical usefulness, as expected differences may fall within the day-to-day variability of these markers. Consequently, correct interpretation of HR or HRV fluctuations during the training process requires the comparison with other signs and symptoms of over-reaching to be meaningful.