For additional tips on how to stay hydrated in the hot weather, see below.
As these transcendental summer days beckon with outdoor adventures just a moment away, even as we may be more carefree, a few moments to consider weather safety are paramount to staying healthy. Hot weather increases physical demands on the body (with increased heart rate, decreased blood pressure, decreased oxygen delivery to vital organs, glycogen depletion in the muscles, and build up of lactate build up) to dispel heat. Those with complicated medical conditions like heart disease or failure, COPD, asthma, diabetes, or pregnancy, and some medications (antidepressants, which may blunt thirst; diuretics which can affect fluid balance; some blood pressure medications may reduce heart rate; amongst others) make one more vulnerable to the effects of heat. Attention to hydration, clothing, ambient conditions will keep you ready to optimize every day of sunshine.
Of course, if any questions about safety in the hot weather, please reach out to your medical team to ensure a "Heat Action Plan" specific to your conditions.
Pre-covery (start out strong):
Plan ahead, and consider acclimatization.
Be aware that factors such as humidity, ozone levels, air quality and surface (concrete versus dirt, for example) affect the heat stress of our activity.
If planning moderate to high-intensity exercise (or if Heat Index is in moderate range), drink 8-12 ounces of fluids 30 to 45 minutes prior to activity and plan for 16 ounces of hydration during each hour of activity.
Avoid alcohol 48 hours prior to activity.
Plan to eat carbohydrates (as glycogen stores in the muscles will deplete more quickly in the hot weather).
Have a Plan B - if the Heat Index drifts up, prepare to pivot: exercise early in the morning or evening, consider a local (air conditioned) gym, change venue (shaded, a mall or cooling center) and be flexible to more frequent breaks.
Wear loose-fitting, vented, moisure-wicking clothing (and if possible UPF protected).
Recovery (stay strong):
Within 4 hours drink 150% of the weight that was lost with activity (so, if you lost 1 pound per your home scale = 16 ounces, replace 24 ounces).
Replace electrolytes if sweating vigorously for more than 1-2 hours (consider PediaLyte or electrolyte tablet or powder).
Do not forget protein (will vary per individual, but aim for 15-20 grams within 1 hour of moderate exertion), along with carbohydrates to replenish lost nutrients.
Cool water immersion to help with evaporative cooling.
Avoid alcohol.
Get plenty of sleep.
Resources:
Hydration Fact Sheet, 2017-126.pdf (cdc.gov)
Heat-Related Illnesses, Heat Stress Related Illness | NIOSH | CDC
Heat Index App (although more directed to outdoor safety, reference contains useful information overall): OSHA-NIOSH Heat Safety Tool App | NIOSH | CDC
To Track Air Quality Index, AirNow Mobile App | AirNow.gov
How to Acclimitize, Heat Stress Acclimatization | NIOSH | CDC