Women are not small men!
How gender dictates nutritional needs during training and recovery – Dr Stacey Sims
The recent article written by Dr Jeroen Swart and Ben Capostagno is Fantastic, for MEN.
However Exercise scientist Dr Stacey Sims says “women are not small men” and should use race day guides based on research conducted on and for WOMEN. Dr Stacey Sims served as an exercise physiologist and nutrition scientist in the human performance lab at Stanford University from 2007-2012 where she specialised in sex differences of environmental and nutritional considerations for recovery and performance. Her personal interest in sex differences and performance has been the precedence of her academic and consulting career, always looking at true physiology to apply innovative solutions in the sport nutrition world.
Not only an elite athlete herself, Dr. Sims has extensive experience working with athletes at all levels: from beginning recreational athletes to the Olympians and Tour de France-caliber cyclists. In 2012 she left her full time academic position at Stanfard to become a mum, launch a start up (Osmo Hydration ) and start her own consultancy practice – all to disseminate science into real world applications for athletes, coaches, educators, and colleagues.
Hydration is a complex topic, with even more complex physiology. Plus, women and men differ in their hydration needs during prolonged exercise. In fact, women are three times more likely to develop exercise associated hyponatremia – low sodium in blood-than their male counterparts.
WHAT SHOULD I DRINK?
Unfortunately, a single beverage suitable for all environmental and race conditions probably does not exist.
To maximise water absorption, consideration should be given to beverages formulated with:
a) 2-4% glucose and sucrose to enhance fluid uptake via co-transport mechanisms;
b) sodium, which helps water flow from the intestines into the blood.
Pre-race
Before race: in the 90 minutes leading up to your race, you need to drink as much as comfortable (~500 millilitres) of low-carbohydrate fluid and/or eat watery fruit and vegetables (salted tomatoes or salted watermelon). This is also good time to use a sodium-based fluid load drink (look for a sodium citrate + sodium bicarbonate mix rather than sodium chloride) to maximise body fluid and sodium stores.
During race
It is important to go into a race or training situation hydrated. Remember it is much easier to come back from a low sugar ‘bonk’ (a few minutes after a bit of food) than it is to come back from dehydration (several hours for the kidneys and hormones to kick in for fluid balance)! Your fluid intake during training should allow you to maintain power towards the end of your ride. Drink a “functional hydration” (3-4% carbohydrate beverage/3-4 grams carbohydrate per 100ml) and basing your initial fluid needs on drinking to thirst.
Recent scientific consortium guidelines recommend not exceeding 800ml/hour in temperate conditions and not to exceed 900ml/hour for hotter and/or more intense rides
After Ride
After you exercise, as a general rule, you need to slowly rehydrate over the course of 2-3 hours. Don’t gulp fluid. This is counterproductive for rehydration. Instead consume a combination of an protein-based drink (the amino acids help with rehydration) and watery foods for optimal rehydration and recovery
Further readings:
- Hausswirth C. and Le Murr Y. Physiological and Nutritional Aspects of Post-Exercise Recovery: Specific recommendations for female athletes. Sports Med, 2011; 41(10): 861-882.
- Tarnopolsky MA. Sex differences in exercise metabolism and the role of 17-beta estradiol. Med Sci Sports Exerc, 2008; 40 (4): 648-54.
- Roepstorff C, Steffensen CH, Madsen M, et al. Gender differences in substrate utilization during submaximal exercise in endurance-trained subjects. Am J Physiol Endocrinol Metab 2002; 282 (2): E435-47.
