When our bodies are too hot we sweat to help cool us down. In sports and other intense activities I see many wiping up the sweat with a towel or some other method.
Is there any real benifit to this? Don’t we just have to sweat more to make up for the water you just removed? I guess that it may remove the salts that have built up on the skin, but from a heat management point I don’t see that it helps, and actually hurts.
I am more interested in this topic with activities such as backpacking, where natural water sources might be hard to come, and you have to carry a full day’s water with you, perhaps more.
I assume they are wiping sweat off because it’s uncomfortable to have it dripping down your face… it also gets in your eyes.
I do it for that reason, anyway, not for heat management.
I don’t think that dripping with sweat helps you. All that matters if the surface area of the sweat, so if you wipe away excess you’re fine as long as you don’t actually dry yourself off.
I think it helps - because the temperature of the sweat surface also matters. If you have a pool of sweat on your body, the surface of that sweat is quite cool and therefore the sweat isn’t evaporating very efficiently. After you wipe it off, sweat can evaporate directly from your warm skin.
Eh, the OP touched on what I came here to say…
As sweat evaporates it leaves salt. As the salt content increases the vapor pressure goes down and it becomes a less effective coolant. Wiping off that salty layer gives you nice higher-vapor-pressure watery sweat to work with again.
If you’re working within the heat sink capacity of sweating as a thermal regulation system, you’ll shouldn’t actually get uncomfortably sweaty. The sweat will evaporate as quickly as it is produced… keeping you cool and dry. Being covered in sweat means that the local conditions (e.g. humidity, poor airflow due to clothing) have reduced the ability of the system to cool or that you need to take a break from what you’re doing.
By the time sweat is beading and dripping on you, most of its cooling ability is gone. The most effective sweat is the sweat you’re never aware of because it evaporates quickly.
So wiping it off or not - there may be some small difference in cooling effect, but the discomfort of salty water dripping on you and in your eyes is probably (rightly) of greater concern than which strategy leads to better heat regulation.