Nausea: Don’t Let It Be A Showstopper, Part 2

By Coach John Hughes

Today, I'll conclude this 2-part article by providing my own diagnosis of the factors causing accomplished rider Andy to suffer bouts of nausea on long rides in certain conditions.

Last week, in Nausea: Don’t Let It Be A Showstopper, Part 1, I related to you the dialogue I had with Andy about the various factors that could contribute to the problem (including the weather conditions he rides in, his level of fatigue, his hydration and nutrition, how hard he pushes himself, etc.). Afterward, I challenged you to make your own diagnosis.

Today, we'll check your work!

Following is my own diagnosis, in which I get into the specifics of each area Andy and I discussed, noting some of the mistakes he's making, what might be causal factors, and what he can do to address the situation. (You may well notice some of your own mistakes in some of these areas and be better prepared to address them, as well.)

Coach Hughes' Diagnosis of Andy's Nausea Problems

Note that multiple factors are at work:

I think Andy basically figured it out: high heat + high humidity + plus cumulative fatigue + wrong diet + wrong electrolytes + riding a little too fast = heat exhaustion, one of the symptoms of which is nausea.

Let's take a look at the specifics of each area, how you handle them – and what may be wrong in your approach, Andy.

High heat and humidity: You figured out that these are contributing factors to heat exhaustion.

Hydration: You’re drinking about 55 fl. oz. / hour — that’s a lot of fluid for your GI system to absorb. You should just drink enough to satisfy your thirst — you shouldn’t force yourself to drink more. Drinking too much can cause nausea. You should urinate every 2 - 3 hours with a pale yellow stream. Coke is slightly acidic and may contribute to the nausea. Given how much you’re drinking, significant dehydration isn’t a factor and dehydration of 2 – 3% of your body weight won’t cause nausea.

Cumulative fatigue: You’re good for 100 miles and get in trouble between 100 and 150 miles. You do longer rides up to 375 miles and sometimes 750 miles. However, your base conditioning may not be good enough to do the longer distances too hard and/or too frequently. It may be that you aren’t recovering fully between the big rides. So fatigue accumulates between rides and during a ride and then bites you sometime after 100 miles.

Nutrition: You’re burning a mix of carbs and fat and at your pace the predominant fuel is carbs. You’re a lean rider but still have enough body fat for a long ride.

You are definitely eating enough calories, and perhaps too many. Each hour your consumption of carbs ranges from:

  • 250 total calories, 190 calories of carbs (from 1 scoop Perpetuem, 1 scoop Skratch and 1/8 c trail mix), to
  • 500 total calories, 385 calories of carbs (from 2 scoops Perpetuem, 2 scoops Skratch and 1/4c trail mix).

For most riders 500 total calories per hour are too many to digest, and this may be contributing to your nausea.

Every six hours you eat a lot on top of your hourly intake: 890 total calories, 300 calories of carbs = 100g. This bolus of food, which, in addition to your drinks, is way too much to digest in an hour or so.

Some of your food choices may be contributing to your nausea. Fat is much harder to digest than carbs, and protein is somewhat harder to digest than carbs.

A PB&J sandwich is a good start to the day, although it’s high in fat calories: 35 – 40%.

Perpetuem and Skratch are both good products. When it’s hot, drinking the more dilute mixes of 1 scoop of either Perpetuem or Skratch / bottle will be easier to digest. One of the sports products isn't better than another, and none of them is better than real food and drink. You might experiment with different drinks to see if that affects whether you get nauseous.

You are eating a lot of fat, which is hard to digest:

  • Trail mix: 60% fat calories
  • Sandwich (turkey and cheese or ham and cheese): 45% fat
  • Potato chips: 55% fat

Here are some better choices:

  • Cereal (breakfast) bar: 25% fat calories
  • Veggie sandwich: 10% fat
  • Pretzels: 5% fat

Electrolytes: Read my column What Electrolytes Do You Really Need?. Sodium is the only one lost in significant amounts compared to your body’s store of it. A liter (quart) of sweat contains roughly 800 mg of sodium.

You’re getting 315 to 630 mg of sodium / hour from your drinks. Deli turkey, ham and cheese are great sources of sodium (almost 2000 mg / sandwich!). Three ounces of potato chips have 510 mg of sodium. Three ounces of pretzels have a whopping 1,155 mg of sodium!

One capsule of regular Endurolytes contains 80 mg of sodium; a capsule of Endurolytes Extreme contains 120 mg of sodium.

Salt tablets are great, but may cause an upset stomach.

Pacing: You figured out that riding too hard for the conditions contributes to your nausea. Here’s why:

  • The harder you ride, the more heat you are generating. The human engine is only 20 – 40% efficient. Two scoops of Perpetuem and 2 scoops of Skratch provide about 375 total calories – but only 75 to 150 calories get you down the road. The rest produce heat!
  • The hotter you are, both from internally generated calories and from the environment, the more you sweat, i.e., more blood moves from your core to your skin. Less blood in your core means less H2O in your core, which makes it harder to digest anything.

You should be okay long as you stay at least 5% below your lactate threshold / FTP. You should always be able to carry on a conversation.

In sum, when it’s hot and humid don’t ride long distances as often and don’t ride them as hard. Experiment with different drinks to see if that makes a difference. Eat less and, in particular, eat solid foods with less fat.

My Endurance Training and Riding Bundle of eArticles includes detailed information on nutrition for endurance riders.

My Summer Riding Bundle provides more information on riding in the heat and what to eat and drink.

This fall and winter are great times to address any showstoppers that affect your riding. My eBook Stop Cycling's Showstoppers provides dozens of tips in 10 areas including nutrition, environment, riding aches and pains, equipment problems and how to ride through tough times and other mental issues.

Coach John Hughes earned coaching certifications from USA Cycling and the National Strength and Conditioning Association. John’s cycling career includes course records in the Boston-Montreal-Boston 1200-km randonnée and the Furnace Creek 508, a Race Across AMerica (RAAM) qualifier. He has ridden solo RAAM twice and is a 5-time finisher of the 1200-km Paris-Brest-Paris. He has written nearly 30 eBooks and eArticles on cycling training and nutrition, available in RBR’s eBookstore at Coach John Hughes. Click to read John's full bio.


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