Sweaty business we are in scramblers! Jiujitsu, MMA or grappling, heck even regular exercise in hot weather can reduce us to a sodden t-shirt and regret. More so than ever at this time of year heat and hydration becomes a real problem. Some suck it up and train in a full heavyweight gi summer or winter, others use it as a chance to work on their no gi.
Training in hot weather brings on a physiological cascade. Vigorous exercise and warm/hot weather induce sweat production, which contains both water and electrolytes. Osmoreceptors, sensory receptors that detect changes in cellular fluid balance located in our hypothalamus, set off the thirst sensation, which serves as an early warning to rehydrate (for more on physiology of heat loss). What athletes should drink before (pre-hydration), during (hydration) and after your workouts (re-hydration) is one of the classic topics of exercise science. And a great money earner for certain drinks companies.
Its well known that even mild dehydration can impact performance (Walsh et al, 2007) and make our perception of exercise difficulty worse. Decrements in performance can occur as soon as you have lost one percent of your body weight. Prolonged dehydration from training can impair recovery due to increased oxidative stress and have a prolonged impact on your training. So it pays to stay well hydrated and cool in order to get the most out of your workouts.
What to drink?
The amount of fluid you need depends on the exercise intensity and duration, more intense exercise produces more heat as a result of muscle action. Drinking water alone has a tremendous effect on improving our rate of perceived exertion, but this comes with a kick back. While plain water restores the volume of blood plasma, it inhibits the thirst mechanism before we can get our electrolyte levels are back to normal. It is suggested water-only drinks can only replenish 30-70% of fluid losses. This is why the sports drink was developed, containing electrolytes in the form of sodium and potassium. You can always add a pinch of salt to your water bottle.
If you are training longer than an hour or at a high intensity you will need to consume electrolytes and simple carbohydrates. You can find this kinds of drinks easily in most supermarkets I suggest going 1:1 with water and electrolyte carbohydrate drinks.
Adding carbs improves whole body rehydration and improves muscle and liver glycogen re-synthesis. The absolute best way to optimize your workout nutritional intake especially post training is to ingest a workout drink containing protein and carbohydrate.
What else can you do?
Wear less for one, if you are one of those guys who wears a t-shirt under your gi would suggest swapping it out for a compression layer or a rash guard or better yet nothing at all. Even the the idea of compression wear for heat loss isn’t well supported by evidence a study by Goh et al (2011) and by Houghton (2011) saw no improvement in thermo regulation in either team sports or running. What was found however that perception of heat was improved! Maybe subjects like the feel of the garments and perceive that they can improve performance.
Be less fat. It is well known that poor body composition, is A. Like wearing more clothes (See above) and B. Increases blood viscosity and leads to poorer electrolyte metabolism.
The other less useful solution is simply acclimatise! For those of us in the UK where the weather can switch seemingly at random this isn’t a great solution, but for those of you who are going to compete in hot climates, I suggest head early as it can take up to 2 weeks for the body to become accustomed to a new ambient temperature.
Rehydration is extremely important practice to become accustomed with if you desire to get the most from your training and speed your recovery. So break out the sports drinks or make your own, consider a light weight gi (don’t make your own) and get training.
- If you are training in heat consume a drink with carbohydrates and electrolytes
- Gulp don’t sip for better absorption
- You can make your own sports drinks cheaply
- Consume 1-1.5 litres per hour of intense training ideally half water half sports drink
- Come to training already hydrated