Tuesday, June 14, 2011

The great SWEAT dilemma

I had a short debate on Twitter yesterday with some buddies. They (and many others) are always incredulous when I state that I suffer more than most in the heat. I've lived in South East Asia for about 20 years and as I'm sure you will be aware it is very hot and very humid 24/7 365.

Yes you do acclimatise to some degree but genetics play a major role. The simple fact is that being of Anglo-Saxon heritage not to mention relatively short and compact I heat up very quickly and start sweating at the slightest excuse.

There are three main types of body classification Ectomorph, Mesomorph or Endomorph. Guess which one I am?

(Courtesy of muscleandstrength.com)

An ectomorph is a typical skinny guy. Ecto’s have a light build with small joints and lean muscle. Usually ectomorph’s have long thin limbs with stringy muscles. Shoulders tend to be thin with little width.

Typical traits of an ectomorph:
•Small “delicate” frame and bone structure
•Classic “hardgainer”
•Flat chest
•Small shoulders
•Lean muscle mass
•Finds it hard to gain weight
•Fast metabolism

Ectomorphs find it very hard to gain weight. They have a fast metabolism which burns up calories very quickly. Ecto’s need a huge amount of calories in order to gain weight.


A mesomorph has a large bone structure, large muscles and a naturally athletic physique. They find it quite easy to gain and lose weight. They are naturally strong which is the perfect platform for building muscle.

Typical traits on a Mesomorph:
•Hard body with well defined muscles
•Rectangular shaped body
•Gains muscle easily
•Gains fat more easily than ectomorphs

The mesomorph body type gains muscle easily and very quickly. The downside to mesomorphs is they gain fat more easily than ectomorphs. This means they must watch their calorie intake. Usually a combination of weight training and cardio works best for mesomorphs.


The endomorph body type is solid and generally soft. Endomorphs gain fat very easily. Endo’s are usually of a shorter build with thick arms and legs. Muscles are strong, especially the upper legs. Endomorphs find they are naturally strong in leg exercises like the squat.

Typical traits of an Endomorph:
•Soft and round body
•Gains muscle and fat very easily
•Is generally short and “stocky”
•Round physique
•Finds it hard to lose fat
•Slow metabolism

When it comes to training endomorphs find it very easy to gain weight. Unfortunately, a large portion of this weight is fat not muscle. To keep fat gain to a minimum, endomorphs must focus on cardio.

Yes I'm a 100% endomorph and an additional trait of us short, stocky, round types is that our stocky muscles generate heat more quickly than the other body types AND find it more difficult to eliminate due to our body shape. There is less surface area for the heat to escape, plus the naturally higher fat content of our bodies acts as additional insulation keeping the heat in.

The body deals with excess heat by sweating and in the case of endomorph's the higher levels of heat increase the amount of sweat. Add to that a trained triathlete's sweat glands are highly tuned and very efficient at their job, hence the sweat pours out.

The body sweats in order for the liquid to evaporate from the skin i.e. changing liquid to gas. To convert a liquid to a gas takes energy and the energy used is taken from the heat of your body, thus cooling it.

However, this method of cooling all breaks down in climates with extremely high humidity. The simple fact is that very little evaporation takes place due to the saturated state of the humid air and the sweat simply rolls off the body. It does of course take away some heat but only a fraction as much compared to the process of evaporation.

In my debate I stated that I sweat at a rate of 3 litres an hour - there was "doubt" cast by one or two of the debaters, so here is an extract from Active.com on the subject.

"Average and Champion Sweat Rates

How much do we sweat? An average person sweats between 0.8 to 1.4 liters (roughly 27.4 to 47.3 oz.) per hour during exercise. To help you with a visual, the smaller bike water bottles typically hold 0.6 liters (20 oz.) of fluid and the larger bottles hold 0.7 liters (24 oz.) of fluid.

The highest recorded sweat rate for an athlete in an exercise situation is 3.7 liters (125 oz.) per hour, recorded by Alberto Salazar while preparing for the 1984 Summer Olympics. The highest human sweat rate recorded is 5 liters (169 oz.) per hour measured on a resting body exposed to a hot environment. At rest, the skin blood flow was maximum and not competing with exercising muscles.

How do you know if you are an average sweaty person or a champion sweater? You need to do some testing.

Your Sweat Rate Test

The easiest way to measure your sweat rate is to weigh yourself without clothes on before exercising for one hour. After an hour of exercise, return home, strip down and weigh yourself again. Assuming you did not use the toilet or consume any fluids during exercise, your weight loss is your sweat rate. For each kilogram of lost weight, you lost one liter of fluid. (For each pound lost, you lost 15.4 oz. of fluid.)

If you drink any fluids or use the rest room between the two weight samples, you'll need to include both of these estimated weights in your calculations. Add fluid consumed to the amount of weight lost. Subtract estimated bodily void weight from the total weight lost."
The whole article can be found here.

Most sources I've read state that during exercise a human can absorb between 1 and 1.5ltrs of fluid an hour. Working on the higher level of 1.5ltrs that means that we endomorphs will likely be in a huge deficit in an typical hot/humid Ironman race. I have often lost 10kg in an Ironman and needless to say the second half of the run is pretty ugly.

Again most sources I've read state that performance begins to be negatively affected with just 1-2% of fluid loss. You can start to see how much fun Ironmans become for me at over 13% loss of fluid body weight. See the graph below.

Adapted from Wilmore & Costill (1999) ‘Physiology of Sport & Exercise’. Human Kinetics.

So what to do?

As best as I can work out entering more races in cooler climates is a good call. Sadly though the heat follows me EVERYWHERE. At Ironman China last year I was positively freezing 3 days before the race but come race day it was close to 40C.

Certainly a really disciplined drinking strategy is called for. Especially on the bike where it's easier to ingest. Making sure that there is never a moment when my stomach doesn't have at least some fluid being absorbed. As mentioned earlier though, there is only so much that can be absorbed and if it is below the sweat rate then there's going to be some serious payback, usually somewhere on the run.

So the solution is...? Lose some weight you fat bast*rd...haha That is my solution. Reduce the stress on the body for the hills and the run, reduce the insulation and thus have more of the blood closer to the skin's surface to promote as much cooling as possible. Easier said than done, I'm and endomorph don't forget and I like to party and love food. Add to that, as soon as I start losing weight it goes from my face first and everyone starts telling me I look ill and drawn.

I'll get over the criticism and I'll do my best to HTFU on the diet front. It's been interesting writing this and researching stuff on the net. This is my last hard week of training before a two week taper for Ironman Korea. I'm far from my best but these three weeks can get me close to where I need to be and hopefully a shot at a qualifying spot for Kona. Failing that it'll be all about recovery and then try again three weeks later at Ironman Lake Placid.

Interesting times. I'm just hoping that the heat gods don't follow me to these two races. Needless to say, I check the projected weather forecast for Jeju, Korea ALOT haha.


Matty O said...

Yeah I have a bigger frame... I don't take proper fluids on the run typically.

I don't have a high sweat rate typically though either... so I guess I am lucky I don't have to actually "plan" out my workouts.

Good post though.

Steve said...

this is very helpful. now i know whay i sweat so much even i just pumping air to my bike's tyres.

for me, there are too much fat around my butt and upper legs.

Pete Newing said...

Marathon talk had a good interview with Dr Mark Hetherington - over three episodes starting at episode 70


Worth a listen


Simon said...

Thanks for the feedback Matt

Haha, nice one Steve, yes it was an eye-opener for me. But seems like the solution is as I thought, get the fat down and then hopefully the sweat rates won't be quite so debilitating

Thanks for the feedback Pete. I've not listened to marathontalk yet but was recently recommended that I do from a running friend. I'm gonna download it now.

jantel said...

I agree with you and your sweat rate is definitely accurate. I am at 2.5-2.7L per hour myself, although last tested about 2 years ago, digitally. Electrolytes , electrolytes , electrolytes !