Hydration During Exercise

So it’s January and no doubt there are New Year’s resoluters everywhere. I was going to take this opportunity write about New Year’s resolutions and how we can keep on track. But there are hundreds of blogs out there regarding this subject matter, and considering the crazy temperatures of the last week, I thought it would be important to address hydration to allow you to keep on track with your exercise goals in the safest possible manner.

Soooooo hot right now!

Soooooo hot right now!

When we exercise the body increases in temperature. The way that the body seeks to mitigate this increase in temperature is to sweat, which evaporates off the skin cooling the body. Like heart rate, typically there is a linear increase in sweat rates with an increase in exercise intensity. So the harder you go the more you sweat. Problem being is the potential to become dehydrated quite easily if the exercise intensity and (in light of the past week) temperatures are high. 

Dehydration in a worse-case scenario can lead to fainting, fits, seizures, is one of the main causes of heat stroke and if unattended, death. Best case scenario dizzy spells (due to low blood pressure from low blood volume), lethargy, swollen tongue, dry mouth etc. So even if you’re not dangerously dehydrated, you will still underperform. 

Must have water... need water!

Must have water... need water!

It’s important to bear in mind that we cannot rehydrate as quickly or easily as we lose water during exercise. Gastric emptying times are significantly reduced during a bout of exercise. So you can only absorb roughly 250ml per 15mins at best, when you can easily lose up to 3L an hour of water through sweat, especially considering the aforementioned factors. You may be able to drink more than this when you have a rest beak, but it will still only absorb at that rate, and it’ll be slushing around in your stomach until then.

Also, if you take into consideration that you may not have consumed enough water to satisfy your daily requirements to begin with (roughly 2L per day), and you’re on the back foot from the get go. 

So here are some tips for adequate hydration for exercise and rest:

  • Firstly, ensure that you’re drinking about 2-2.5L of water per day. On a hot day this may be more.
  • About an hour before a bout of exercise, try to drink about 1-1.5L of water. This time frame allows time for water absorption the need for urination before, not during exercise.
  • Speaking of urination, check your wee. The darker the wee, the more fluid you require. Dark orange? You’re in a bit of trouble. 
  • During exercise, only drink about 250ml per 15mins.
  • Weigh yourself before and after training. For every kg of weight lost replenish with 1.5L of water. The extra 0.5L accommodates for the higher metabolic rate that your body is in post exercise, as it takes a little while for it to reduce to resting.

Easy? No sweat (sweat pun…. get it?)

Michael Pegg

Exercise Physiologist

B.ExSci&Nut, M.ClinExPhys, AEP, ESSAM

Michael is a masters qualified Exercise Physiologist with 5 years of clinical experience. During this time he has successfully applied exercise protocols to treat neurological, metabolic and cardiopulmonary disease. Michael is also a Ju Jitsu coach and Tai Chi/Qi Gong instructor.

In addition to our Lungs in Action class, individual sessions, small group training and other targeted classes, The Movement Team now offers a new weekly Tai Chi/Qi Gong class. For bookings or questions please contact the clinic.