Exercise and Hydration

It appears as though summer has finally arrived to stay and, along with it, the difficult decision of venturing out to enjoy the outdoor exercise opportunities that present themselves, or the attraction of lounging around in the shade, pina colada in hand.  For many of us, fitness takes precedence over leisure, especially given the chance to take advantage of the relatively small window of sunshine the West Coast offers. 

     Unfortunately, the warmer temperatures are not conducive to vigorous exercise.  A few hours of heavy exercise in a hot environment may result in significant water losses.  Sweating is the body's natural refrigeration mechanism, moving warm blood from the body's core to the skin, where a cooling effect occurs as the fluid evaporates.  The cooled skin then serves to cool the circulating blood as it returns to the core tissues.  The unfortunate side effect of this is that the exercising muscles require oxygen to perform muscular activity, and with most of the blood being shunted to the surface for cooling, less oxygen is delivered to working muscles.  The result is greater reliance on other means of generating energy, which produce lactic acid and the earlier onset of fatigue. In addition, sweating depletes the blood of water, which is needed for the maintenance of circulation.  The result is less blood being delivered to the muscles with each heartbeat, and a compensatory increase in heart rate in an attempt to counteract this reduction in blood pressure. 

     What all this means is that at any given workload, your heart is working harder to deliver less oxygen to your muscles, because of the competition between your exercising muscles and the cooling of your deep tissues.  The best way to combat this losing battle is through adequate hydration.  Here are some tips:

·        Consume 400-600mL of cold water about 20 minutes prior to exercise

·        Consume 250mL of cold water for every 15 minutes of continuous exercise.

·        Consume 500-750mL of cold water for every 1lb. of body weight lost during exercise.

·        A small amount of salt and sugar may be added to a rehydration beverage to aid in electrolyte and energy replenishment.

 

 

Mike Wilson is the head trainer for PURSUIT Training and Rehabilitation.  PURSUIT has recently expanded its services to Richmond, BC.  Both the Surrey and Richmond locations offer complete sport conditioning and rehabilitation services, as well as adult conditioning programs. 604-574-2895.

 

Mike Wilson

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