Don’t Sweat It, You Can Train To Perform In The Heat

Summer is here, and it’s a hot one across the country.  Don’t let the heat beat you up, keep you from having fun or having success.  When we first experience summer’s furry, our bodies are not prepared to run the internal swamp cooler.  As we overheat in those first hot days, our heart rate spikes, efforts are difficult to maintain, we feel wiped out after a minimal workout, and our muscles are more tender than expected afterwards.  However, with a thoughtful training block targeted to stimulate adaptation to heat, we can perform in the summer with minimal ill effects.

Why We Suffer in the Heat; a Little Physiology Lesson

sweat physiology

  • To sweat and cool, blood, which carries heat generated by working muscles, needs to flow to the skin. Blood caries heat generated by working muscles. With blood being diverted from our muscles and heart, power and endurance are diminished.
  • Sweat is comprised of plasma and electrolytes. Increased sweating depletes these resources from the blood, making it thick.  Thick blood (low blood volume) is taxing for the heart to pump, so heart rate increases to sustain the workload.  An endurance pace may feel like a sprint.
  • With less oxygen-carrying blood making it to our muscles, aerobic capacity, the oxygen fueled energy system relied upon for long duration efforts, is decreased and we must rely on carbohydrate-greedy anaerobic metabolism, which is sustainable for only a short duration and is the primary culprit for delayed-onset muscle soreness.
  • With reduced blood volume, VO2 Max is reduced, meaning our bodies are not able to take in as much oxygen. This means that we are less efficient and are putting more stress on our bodies for any exertion.

Fortunately, we are incredible at adapting to heat.  Once adapted, if we continue to train in these conditions a few times a week, we will return to our previous fitness profile.  If we actively work on acclimating to hot conditions, it can be accomplished in 10 – 14 days.

 Hiding in the Cool Will Not Help You Acclimate


Keep Cool While Adjusting to Hot Environments


  • Stay out of air conditioned spaces to adjust to the heat, but do not get hot. Keep cool with a fan, cold showers, dips in a lake, etc.
  • If you can, sleep with the windows open. However, if it is too hot to sleep, use the AC sparingly (set it to the warmest temperature you are comfortable in).
  • Drink as much water as you can, alternating pure water with electrolytes. Avoid/ reduce caffeine and alcohol intake while acclimating as they dehydrate you.
  • Stay out of the sun when not training, and do not get sunburnt! A burn will reduce your ability to sweat.
  • If you are traveling to an environment that is more warm or humid than your home turf, arrive as many days before the event as possible.

Guidelines for Heat Adaptation Training Block


holly running (2)
Once Heat Adapted, You Can Be Successful Racing and Training in the Sun

After training for an hour a day for two weeks in peak heat with two rest days in the mix, the body should be adapted.  If we train to exhaustion, overheat, neglect our nutrition, or don’t recover from training sessions, the process will take longer- often much longer and to the detriment of our fitness.


  • Pre-cool your body with a cool shower or spending time in an air-conditioned area before you work out.
  • Wear clothes that wick moisture away from your skin. Avoid cotton, tight filling garments, and dark colors.
  • Train through the peak of the heat each day for a short period of time. Heat stress sessions for one hour a day will trigger a physiological response. Increase the time or intensity each day, but do not stay out if you start to feel excessively hot or fatigued.  You want to stimulate your body to adapt to the heat, but if you stress your body too much you will spend your rest time recovering instead of adapting.
  • Ease up. Slow your pace, reduce the time, and decrease the weight/reps if power training.

Maintain Heat Adaptation

  • After this adaptation period, slowly increase duration or intensity of your workouts in the heat.
  • Train for at least one hour, twice a week in the heat to maintain physiological adaptation.
  • Unfortunately, it only takes 5-7 days to lose heat adaptation.

Train to Refuel and Rehydrate in the Heat

Some of the Electrolyte Products in my Pantry

When it’s hot, our appetites are suppressed, and drinking feels like a chore.  However, we will not be able to do endurance or intense workouts in the heat if we don’t refuel and rehydrate while exercising.  Fortunately, we can train our bodies to digest food and absorb liquids.  When our digestive tracks are not heat adapted, a sour stomach, bloating or the feeling of liquid sloshing around in our bellies is common.  These usually lead to stomach cramps and we stop refueling and rehydrating.  This leads to disaster! Eat a good meal three hours or more before a heat stress workout.  It will take three hours to digest this meal.

  • Eat a good meal three hours or more before a heat stress workout. It will take three hours to digest this meal.
  • Drink while exercising, and make sure you are hydrated before you start.
  • We need to drink more water than usual when training in the heat. In arid climates, it is easy to think we don’t need to replace lost fluid because our sweat is evaporating so rapidly our skin and clothes are dry.  Aim to drink .5 – 1L of fluids per hour. Drink even more when in conditions like Death Valley or the Amazon.
  • Freeze half of liquids in a bottle/ hydration bladder, or fill bottles 2/3 with ice cubes. Hot liquids are unpleasant to drink and are generally still untouched when we finish training, leaving us completely wiped out.  Cool liquids will help cool your core temperature too.
  • Replace lost electrolytes. Alternate pure water and electrolyte mix during training sessions or follow hourly training dose guidelines for specific electrolyte tablets like MetaSalt or Endurolytes.
  • It is hard to digesting food in the heat. Err on the side of moist carbohydrates such as sports drinks, gels, blocks, rice balls, etc. instead of dry bars, sandwiches, trail mix, and the like.  Fats and proteins are especially hard to digest in hot conditions.  Avoid them during workouts or add them in carefully.
  • You will burn calories keeping cool. Consume more calories than you usually do.

What Physiologically Changed During the Heat Acclimatization Training Block?

  • Our blood volume increases. Blood no longer becomes thick and taxing for the hearts to pump.  Heart rate and V02 max return to normal zones.  Efforts feel as they should: endurance pace no longer feels like a fast pace, and sprints are fast again.
  • Our cardiac output increases. We can now get oxygen-carrying blood to our organs, working muscles and skin at the same time.  This returns our endurance, recovery between intervals and power to normal, and it diminishes Delayed Onset Muscle Soreness (DOMS).
  • We sweat more profusely at lower temperatures but with less electrolytes lost. This lets us dump heat efficiently and reduces cramps.
  • We also improve fluid and nutrient absorption. We can now fuel our long sessions and intense efforts.

Traveling to a Hot Location to Race or Adventure In?

fun in the heat
Heat Adapted Athletes Having Fun
  • Arrive in the climate as many days prior to the event as possible.
  • Spend the two weeks before departing adapting to heat by training in the warmest location available. Be creative!  Crank the heat in a small room for a trainer session, go to Bikram yoga, train in excessive layers, etc.
  • If the destination will be humid and you live in arid conditions, you will want to adapt to this as well. In humidity, sweat does not evaporate well off our bodies.  Find a steam room to use daily and increase the time in it each day in addition to heat stress training.  Our bodies will adapt to this too if asked nicely.
  • Continue the adaptation routine on arrival, but do not get exhausted before the big day! Training days should be short, at an easy effort, and ended before the heat is impacting performance.  Cool down as soon as the training session is complete.

Summer heat?  Bring it on!

A Lowlander Racing in the Highlands – How to Not be Crushed Competing at High Altitude.

Oxygen Amounts at Altitude

I grew up at 7000 ft. altitude in New Mexico, spent my early adult life living in Utah where I trained and played in elevations above 8000 ft. regularly, but I now live in Oregon at 3000 ft. and am learning the unique pain and challenges of racing in high altitudes when I live and train at low altitude.  This summer I have three races in high altitudes: the Chile Challenge Pro XC at Angel Fire NM, National Championships at Mammoth CA, and the BreckEpic at Breckenridge CO.  This schedule has given me the opportunity to be my own “guinea pig” of how to prepare for this added challenge.

Dial down the intensity when you arrive at altitude to acclimate better and enjoy the scenery!
Dial down the intensity when you arrive at altitude to acclimate better and enjoy the scenery!

For us lowlanders, a trip to the Rockies is a humbling experience.  A hill I would normally warm up on has me gasping for air, two hours into a casual paced ride will have my legs burning, my après ride festivities are reduced to sleeping, and the next morning I don’t feel as fresh to pedal as I expect.  Altitude!  So what is going on?  The atmospheric pressure is less at high altitude making less oxygen available in each breath of air you inspire.  Oxygen is captured in the lungs, transported by hemoglobin in blood, and delivered to muscles so they can fire.  Respiration and heart rate must increase at altitude to get the same amount of oxygen to muscles from what is needed at lower altitude.  If you live or regularly train at elevation your body will physiologically adapt to transport more oxygen.

Acclimatization to Altitude
Acclimatization to Altitude

When I get to high altitude my body:

  • Reduces the plasma (liquid) in my blood, thus increasing the concentration of oxygen carrying hemoglobin being pumped through the circulatory system, but making my blood thick.
  • It takes more oomph for my heart to pump my thickened blood, so my heart rate increases.
  • To get more oxygen to my lungs, my respiration rate increases.
  • Muscles lose their ability to use fatty acids for fuel and rely primarily on glycogen.

If I can stay at high altitude for 3-4 weeks my body:

  • Will increased the amount of red blood cells and hemoglobin allowing plasma levels return to normal and my blood is no longer sludge.
  • Resting respiration and heart rate decrease to my pre-high altitude zone.
  • Mitochondria (muscle cell’s power producers) increase in size and number so fueling during exercise returns to a predominance on fatty acid consumption instead of glycogen.
  • Increases erythropoietin hormone (EPO) to increase red blood cell and hemoglobin production.
Plan more carbs and more total calories at altitude.
Plan more carbs and more total calories at altitude.

In a world where I don’t have a job and have unlimited funds, I would travel to my high altitude race destinations a month before the race, but until I am rich and famous I have to be smart about how I prepare and interact with altitude.  There is a lot of conflicting research about when the negative effects of altitude are the most intense for athletes but it is general agreed that immediately upon arrival at altitude your body starts to respond by increasing respiration, increasing resting heart rate, and decreasing blood plasma.

I decide to arrive at altitude under 24 hours before my race:

  • The physiological effects will have had the least time to exert their negative influence on my body: my blood is not complete sludge, I still have untapped glycogen stores, and if my sleep is poor due to my racing heart I’ve only had one meager night of sleep instead of several.
  • When I pre-ride the race course and tune-up, I do so at a less intense effort (10-20% reduction) than I normally would.  However following my active routine will help me acclimate better than just relaxing.
  • It is easy to become dehydrated at higher altitude because I am shallowly breathing dry air more rapidly allowing fluid to be lost with my respiration. The dry air also evaporates my sweat so quickly I may not know I am loosing fluid this way too. I increase not just my water intake, but my electrolyte intake as well.  Sadly, I eliminate diuretics from my diet – no caffeine or alcohol.
  • Appetite is suppressed by hypoxia, my body uses more energy at rest than at low altitude, and my body poorly uses fat stores as fuel at high altitude. I shift my eating routine to frequent, carbohydrate dense meals to maintain my energy levels.  I also east iron rich foods (broccoli, lean red meat like elk and kidney beans) to support my hemoglobin and anti-oxidant rich foods (berries, russet potatoes and cinnamon) to repair cellular damage caused by not enough oxygen getting to my muscles.
  • Sleep!  My sleep is disrupted, I am using more energy just sitting on the couch, and my body is in overtime working to adapt to oxygen depletion so I schedule naps throughout the day.
Preparations will get the whole crew to the summit.
Preparations will get the whole crew to the summit.

I may be at a disadvantage racing at altitude compared to my competitors who live or train at high elevations, but having a plan based on physiological effects to manage the impacts gives me an edge over those who do not prepare.  For me, knowing what to expect from my body at altitude gives me confidence to race well. I will rely on a slightly less intense effort while focusing on consistency; I will be the tortoise not the hair during the race.  If mid-race I have to put in a sprint effort I will quickly replace the glycogen used by eating a gel.  After all, very few competitors live at high elevations and all of us are suffering with reduced oxygen.  So, how is my strategy working for me? Stay tuned and I’ll break down what worked, what didn’t, how I changed my plan of attack at Angel Fire to Mammoth and what I’ll be doing to get ready for six days of racing above 9000 ft. at the BreckEpic in August.