What’s Normal When It Comes to Sweat? 

On average, the human body has around two to four million sweat glands. While perspiration can be embarrassing, it’s also an important bodily function. Of course, some people seem to sweat more than others. So what’s normal?

The science of sweat

When it comes to the science of sweat, it all comes down to the body’s efforts to cool itself down. Sweating sees the body release a salty liquid from the sweat glands, which is designed to evaporate and create a cooling effect.

The process is regulated by the autonomic nervous system, which uses the neurotransmitter acetylcholine to send signals to the sweat glands. Ducts then release sweat to the surface of the skin, which should technically evaporate and act as a natural air conditioner.

Interestingly, the number of sweat glands in the body doesn’t change as the body ages. Dr. Eugene Bauer, chief medical officer at Dermira explains, "From baby to adult, the number of sweat glands does not change. Therefore, babies have the highest number of sweat glands per square inch, i.e. 8 to 10-fold higher than adults.”

Stink and stains

When it originally seeps through the glands, sweat is odourless and colourless. However, when sweat is mixed with bacteria on the skin it breeds body odour. The apocrine sweat glands can also cause trouble, with proteins and fatty acids giving sweat that dreaded yellowish look.

While some people seem to always be sweating, others stay bone dry. According to the experts, this kind of fluctuation isn’t unusual.

"The normal range for sweating is very wide," assures Dr. Robert Sallis, co-director of the sports medicine fellowship at Kaiser Permanente Fontana Medical Center. "Some people might only sweat half a litre during an hour of intensive activity, while some might sweat 3 or 4 litres, and both are still within a normal range."

Size matters

One of the biggest sweat influencers is a person’s size and gender, which play a role in how and where they sweat. Fitness can also affect patterns, with overweight people usually sweating in central areas like the chest and back. In comparison, fit bodies tend to distribute sweat evenly. Women typically sweat less than men, which is usually because they have fewer sweat glands and less muscle mass.

Of course, there are some exceptions to the rule. Lack of sweat can be a tell-tale sign of heatstroke, which can hit after prolonged exposure to high temperatures. Nerve damage can hinder the body’s ability to sweat, with skin diseases like psoriasis or heat rash also interfering. Over sweating can also be an issue, with menopause a common complaint. Stimulants like spicy food and nervousness can trigger sweating via the sympathetic nervous system, while hyperhidrosis describes the condition of overactive sweat glands.

The billion dollar sweat market

Thanks to sweat glands, the antiperspirant market is saturated with choice. Some brands rely heavily on consumer grade chemicals, which means analytical labs are under constant pressure to perform. ‘A Closer Look at Chemical and Solvent Demands for LC-MS Applications’ offers a glimpse at the latest technology from Honeywell, and how it’s fast becoming a routine apparatus in modern analytical laboratories.