Sports Nutrition

With all the talk about hydration, sweat rate, electrolytes, carbo loading, etc. I decided to put together a spreadsheet to help sort everything out. Dug out about a half dozen sports nutrition books and my old notes from graduate school and made some calculators that determine:

*sweat rate
*fluid intake needed during exercise
*daily macronutrient intakes (carbohydrate, protein, fat) in grams and calories based on average number hours/training/day
*daily total calories based on avg hours training/day
*grams CHO (carbohydrate) needed during carbo loading up to 6 days pre-event
*grams CHO needed 1-4 hours prior to event
*grams CHO needed during event
*grams of CHO and protein needed during recovery (within 30 min of finish up 'til next full meal)
*list of supplements and what's in them (there's plenty of space for you to add more)

This is still a work in progress and has limitations:

*My hydration calculator does not take into account water losses from respiration or urination (who measures how many ounces they pee in the woods?).
*The macronutrient calculators are for ENDURANCE athletes, not strength/power/hypertrophy athletes.
*The total caloric needs are based on maintaining body weight, not weight loss or gain.

Once you've plunked in your body weight and gotten all of the grams and calories of each macronutrient you need, you have to be able to measure what you are actually consuming. I use and recommend FitDay, a nutrition tracking software that can be used for free (online version). You can also download a dirt cheap version that has a few more features, and you can add your own foods to the database.

Let the calculating begin!

Sweat Rate

I think I've finally figured out a reasonable strategy for fluid and electrolyte replacement!

Lately I've been anal retentive about documenting my pre and post run weight, fluid intake, electrolyte intake, etc. As it turns out, I've only been drinking about half of what I should be, which can be a BIG contributor to muscle cramping. I've been somewhat reluctant to gulp down lots of fluids because: a) fear of hyponatremia, especially being a salty sweater, b) I don't want an upset/sloshing stomach while running, c) I never needed that much fluid during road runs, d) most of the peer reviewed literature suggests that it's best to be a little dehydrated than overhydrated, and e) I don't want to be pissing like a race horse during a trail run.

Last weekend at Afton, I calculated my sweat rate to be 2.25 lbs/hour, meaning I need to drink 36 oz of fluid/hour to maintain my body weight (I only drank 32 oz for the 2 hours I was out there - less than half of what I should have). I also took 1 S cap/hour and didn't have any problems with cramping or hand swelling.

Today at Hyland, my sweat rate was 2.1 lbs/hour, meaning I need to drink 33-34 oz fluid to maintain (I drank 16 oz/hr + 1 S cap). Pretty close to what I'd expect compared to Afton, especially since Hyland is easier terrain to run on.

Game plan for Saturday at Afton = 36 oz HEED/hour + 1 S cap/hour, which works out to about 400 mg Na/hour (recommended range is 200-500 mg Na/hr) and 21 mg K/hour (recommended range is 20-50 mg K/hr).

If I cramp up this time, it will most likely be because of muscle fatigue due to deconditioning rather than dehydration or electrolyte imbalance. And the cramping will most likely take place in the grass that is taller than I am on the snowshoe loop. I hope I don't get lost.... ;)