WHAT IS YOUR SWEAT RATE & WHY DOES IT MATTER?

WHAT IS YOUR SWEAT RATE & WHY DOES IT MATTER?

Calculating your sweat rate is the best way to figure out how much water you need to be drinking when working or exercising in the heat.

You can use our sweat rate calculator (see below) to figure out your average sweat rate, and how much water you should drink back after your exercise bout or work day.

WHAT YOU NEED TO DO TO GET AN ACCURATE SWEAT RATE CALCULATION:

  1. Pick an activity (ideally during your typical workday) that is 30-60 minutes long, where you are usually sweating. Note that you will need to weigh yourself (nude) before and after the activity, so if this is not possible at work, then go for a run at home or the gym, or do some sort of aerobic (endurance) activity that gets your heart rate up & causes you to sweat (e.g., elliptical, cycling, etc).
  2. Weigh yourself (nude) before exercise and/or work. Write down this number. Go do your activity – and be sure to keep track of the time (be as precise as possible). Note: During this exercise period, you should not use the restroom or drink any fluids. Immediately after you’re done, take your clothes off & wipe off any dripping sweat from your body.
  3. Weigh yourself (nude) again. Write down this number. Enter your two body weights & your exercise/work duration in the calculator below to get your sweat rate & how much water you should drink back!

Sweat Rate Calculator

 

Note that the amount of water to drink back is the amount specific to the activity you did (and that amount of time). If it’s really hot outside, your sweat rate might be even higher, and then you’ll need to drink even more water.

**Remember that you can’t just chug all of that water at once because your body can only absorb it so fast.. as a general rule of thumb, your body can only absorb ~1 cup (8 oz.) of water every 15 minutes, so try to divide up your fluids (over the hour) based on that rule.

For more information, check out our blog on staying hydrated during the workday.

THIS IS A GOOD PLACE TO START, BUT FOR MORE CUSTOMIZED HYDRATION PLANS & RECOMMENDATIONS SPECIFIC TO YOUR SITE, WORK ACTIVITIES, AND CLOTHING, CHECK OUT KENZEN’S HEAT SAFETY PROGRAM– WE’RE HERE TO HELP.

STAY HYDRATED DURING THE WORKDAY!

STAY HYDRATED DURING THE WORKDAY!

Water is essential to our body. It helps to digest foods, makes up a large portion of our blood volume, helps maintain our blood pressure, is a large component of our muscles (~80% of your muscles are water!), and helps to regulate our body temperature. Not only can dehydration impact your mood, but it can also impact your work in the heat.

Working in the heat is already hard enough mentally and physically. But if you’re dehydrated on top of that, you will experience even greater physiological strain, and you might notice that your mood and cognition are worse too. This combination of being dehydrated AND working in the heat will increase the odds of accidents at work, decrease your performance, and increase your risk for heat-releated injuries and illnesses. But don’t worry, there is an easy fix for this…. drinking water!

So how do you stay hydrated throughout the work day?

  • Start by drinking a glass of water when you wake up in the morning. Starting your day hydrated will help to keep your core temperature lower by allowing for your body to sweat adequately (and get rid of heat) throughout the work day.
  • If possible, carry a water bottle with you throughout the day to make drinking water easy and accessible. If it’s not cold water, don’t worry about it. Although it may not be pleasant to drink, warm water won’t necessarily make you hotter.
  • Don’t limit your water intake and always drink when you’re thirsty.
  • NIOSH & OSHA recommend drinking ~8 oz water (1 cup) every 15-20 minutes. But may not be the correct amount for you. For a more accurate hydration plan, you’ll need to calculate your normal sweat rate. Kenzen can help you & your team with this. But for right now, you can weigh yourself before vs. after your workday to figure out exactly how much water you lost (through sweating).

Rule of thumb: you need to drink 20 oz. (about 1.5 water bottles) of water per pound of body weight lost through sweating.

  • Limit alcohol intake. Alcohol dehydrates you and impacts your body’s ability to properly regulate body temperature.

  • Good news: if you regularly consume caffeine, it will not impact your hydration or your ability to work in the heat. So don’t worry about having your 2-3 cups of coffee or tea each day.

How can you check to make sure you’re staying hydrated?

Your urine color (in the toilet bowl) should be a lemonade color (or lighter). This is the easiest way to check that you’re hydrated.

If you’re using a porta-potty where it’s hard to see your urine color in the toilet bowl, you can count how many times each day that you have to use the restroom.

If you’re urinating at least 7 times per day, you’re hydrated. Any less than 5 times per day and you’re likely dehydrated. This would mean that you’re urinating at least once every 2 hours or so.

Glass of water

Three tricks to increase your water absorption:

  1. Lightly salting your foods (especially during the first two weeks you’re working in the heat) can help your body to absorb more water.
  2. Drinking fluids with electrolytes (especially sodium) will help to absorb the water you drink. Just watch those sugars in the drinks- you don’t need them!
  3. Your body can only absorb water at a certain speed… what that means is that you need to pace yourself in drinking the water back after working hard in the heat. You can’t just “chug” a bunch of water at the end of the work day— you will just urinate it out.

Rule of thumb: your body can absorb ~8 oz. (half of a water bottle) every 15 minutes, so try to pace your water drinking to that rate.

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REFERENCES:

  • Armstrong, Lawrence E., et al. “Urinary indices of hydration status.” International journal of sport nutrition 4.3 (1994): 265-279.
  • Kenefick, Robert W., et al. “Quantification of chromatographic effects of vitamin B supplementation in urine and implications for hydration assessment.” Journal of Applied Physiology 119.2 (2015): 110-115.
  • Burchfield, J. M., et al. “24-h Void number as an indicator of hydration status.”European journal of clinical nutrition 69.5 (2015): 638-641.
  • Tucker, M. A., et al. “Reliability of 24-h void frequency as an index of hydration status when euhydrated and hypohydrated.” European journal of clinical nutrition (2016).
  • Ely, Brett R., et al. “Hypohydration and acute thermal stress affect mood state but not cognition or dynamic postural balance.” European journal of applied physiology 113.4 (2013): 1027-1034.
  • Armstrong, Lawrence E., et al. “Mild dehydration affects mood in healthy young women.” The Journal of nutrition 142.2 (2012): 382-388.
  • Shirreffs, Susan Margaret, et al. “Post-exercise rehydration in man: effects of volume consumed and drink sodium content.” Medicine and Science in Sports and Exercise 28.10 (1996): 1260-1271.
  • Bain AR, Lesperance NC, Jay O. Body heat storage during physical activity is lower with hot fluid ingestion under conditions that permit full evaporation. Acta Physiol (Oxf). 2012;206(2): 98–108.