Essential Sports Nutrition

7/19/19

Training in the heat - nutrition tips



Triathletes and endurance athletes are very susceptible to dehydration and even more so, a heat-related injury at this time of the year. Whereas in the cold/cooler months of the year, athletes can get away with haphazard fueling and hydration strategies and poor pacing, now is the time in the year when a poorly planned fueling/hydration regime and pushing too-hard or too-far will negatively affect workouts, adaptations and health.

Let it be known that training in the heat is incredibly stressful for the body. Seeing that training (in any environment) already creates difficulty for the body to adequately digest and absorb nutrients and fluids, you can imagine why so many athletes experience harmful health issues, GI struggles, extreme fatigue, heat stress, dehydration and so many more issues during the summer months when training for an event.

As an example, exercise increases body temperature. The harder and longer you train, the higher your resting temperature. Your body compensates by moving the extra heat to the skin via the blood - it then dissipates into the air through sweat (so long as humidity levels allow for evaporation). But when you exercise, your blood serves another important role - it carries oxygen and nutrients to the muscles. Blood is shared between the muscles and the skin. The higher your core temperature, the more blood is used for cooling and less for the working muscles. In other words, your body will always sacrifice muscle function for temperature control. This is why an athlete's body will begin to "shut down" when overheating as this state is life threatening.

Every athlete has his/her own threshold for when the body begins to experience a decline in health and performance as a result of heat stress, dehydration and glycogen depletion.

To keep your body functioning well (in training and on a daily basis), it's extremely important to care for your body with proper fueling and hydration strategies before/during/after workouts and to respect the conditions by pacing appropriately.

Don't be the athlete who......


  • Does not stay well-hydrated on a daily basis (before/after workouts and during the day)
  • Does not bring along fluids/nutrition when running (especially when running off the bike)
  • Is not comfortable drinking while running/riding
  • Rations fluids to avoid stopping (or does not have enough places to refill bottles)
  • Does not have enough hydration bottle cages on the bike (or if they are on, they are not easily accessible)
  • Does not use sport nutrition products properly (not enough or too much carbohydrates, fluids and electrolytes)
  • Does not use sport nutrition products or does not plan ahead and relyies only on water (or nothing at all)
  • Feels it's only a  "short" workout - so you don't need to fuel/drink


There are dozens of excuses and reasons why fluid/electrolyte/calorie needs are not being met during training and racing and not only is it holding you back from training consistently and executing well during workouts, it is also extremely damaging to the body - placing you at risk for injury, sickness, burnout and other serious health complications. Remember - you are not just fueling/hydrating for one workout but for the next series of workouts. If you struggle during one workout, it will affect your future workouts.

Common side-effects of dehydration and heat stress:

  • headache
  • dizziness
  • blurred vision
  • loss of focus
  • chills
  • high heart rate that won't drop even when you reduce the effort or stop
  • no appetite post workout
  • excessive sleepiness
  • extreme weakness
  • low blood pressure
  • stop sweating
  • dry mouth
  • dark urine
  • dry skin
  • no/little urination
  • extreme cramping
  • bloating/puffiness
  • excessive thirst/lost of thirst
  • rapid, elevated pulse (despite effort slowing down)
  • muscle spasms (during and post workout)

Are you currently experiencing any of the above?
If yes, your current fueling/hydration and pacing strategy is NOT working for you.


Every human body is different so you must pay very close attention to your body signs/symptoms/signals when it comes to training and racing in endurance events. If you do not make the effort to keep yourself in good with proper fueling and hydration (and pacing), you will be forced to spend a lot of time getting your body healthy again before you start even thinking about training again.

To help you out, here are a few very simple tips to help you adapt during hot-weather workouts


  • Sip frequently in small amounts, don't gulp fluids. Gulping (especially from a straw) causes you to swallow air, which can cause bloating and belching. This also may disturb the function of the stomach and slows down absorption.
  • Be sure to have a sport drink with you for all workouts lasting more than one-hour - this should contain a mixture of electrolytes, carbohydrates and fluids in an appropriate concentration to digest well and to be efficiently absorbed. I suggest a hypo or isotonic solution with ~20-25g carbohydrates per every ~12-16 ounces and at least 250mg of sodium to optimize gastric emptying.
  • Aim for 24-32 ounces of fluid on the bike per hour and at least 10-12 ounce fluid for every 30 minutes while running (this should be in a sport drink - not plain water in the heat!).
  • Aim to sip your bottle on the bike every 10-15 minutes (you need at least 3-4 gulps to ensure that you are getting in around 3-4 ounces of fluid) and 1-2 sips every 5-8 minutes while running. Frequent drinking on a schedule will not only help to delay fatigue and prevent dehydration but will prevent overdrinking on fluids (particularly ice cold water), which often causes a sloshy stomach.
  • While keeping your insides hydrated is critical, consider ways to keep your body cool on the outside. Suggestions include exercising early morning or in the evening and avoiding workouts in the heat of the day (10-5pm). Choosing indoor workouts over outdoor when health may be compromised (extreme heat). Using water/ice to cool yourself while exercising. Wear a cooling towel/cooling sleeves. Use a visor over a hat. Choose shady areas over direct sunlight. Wear sunscreen to prevent burning. Wear protective clothing.
  • Always plan ahead with your bottle refill stops. Be sure to STOP before you really need to stop so you are never rationing your fluids or going without.
  • Be sure you are setting yourself up for good hydration actions. Cages/hydration systems on the bike should be accessible and easy to use in ALL conditions (ex. bumpy roads, rain, technical courses, rain, etc.). Your run courses in training should allow you to refill bottles that you bring with you OR set up bottles on your course. Everything you do in training should be practice for race day.
  • Wear a hydration belt/pack so you can drink what you drink, when you want to drink it. There are many types on the market - find one that works for you and never run outside without it.
  • Do not wait for thirst to kick in during endurance workouts/racing to start drinking. Start drinking/fueling early. An athlete who waits to drink until he/she is thirsty is already behind on fluid requirements and many times, this will cause an athlete to drink an excessive amount of water. This may cause hyponatremia (very serious health condition) or may cause a sloshy stomach/bloating/stomach cramping. When you fall behind on your fluids, you will likely drink too much at once to play catch up (often a hypertonic/concentrated amount from guzzling a lot of drinks at aid stations or stops at gas stations in training).
  • Make your fueling/hydration strategy during workouts as simple as possible. You should not be using several different methods of consuming electrolytes, calories/carbohydrates/sugars and fluids. But ok to use 2-3 different products/flavors to help with taste bud fatigue. Also, DO NOT overconcentrate your flasks/bottles.
  • Pace yourself and be OK with slower paces that will elicit a higher RPE. Even mild dehydration can negatively affect performance and can cause drowsiness, irritability, loss of concentration and headaches - none of which are performance enhancing or healthy. When dehydration worsen, serious issues occur which affect the heart, brain, muscles and organs (ex. kidneys).
  • If you overwork your body, it is not possible to overfuel/hydrate the body to meet your training/racing demands.
  • Be respectful of your body in the heat. If you are feeling any changes with your body that concern you, first slow down. Don't be a hero and push through - stop! Remind yourself that when your body starts to shut down or gives you signals/signs that something is wrong (ex. headache, chills, vision changes, etc.), your body is no longer adapting to training stress but it's trying to protect you. Never get upset at your body for a bad workout or race if it is simply trying to protect you from a serious heat or other-related injury.


There are far too many athletes failing with workouts and experiencing negative health issues due to poor fueling/hydration strategies before/during/after training and improper pacing. Sport nutrition is a complicated area with many misguided tips and suggestions that are not always practical or healthy. If you know someone who can benefit from this blog, please share.