Ep 9. Why is Sweat Salty

In Operation Ouch season 8 episode 9, entitled "Why is Sweat Salty," identical twin doctors Chris and Xand van Tulleken investigate the science behind sweat and its unique properties.

The episode begins with the twins meeting a group of athletes training for a triathlon. They explain that sweating is a natural bodily function that helps regulate body temperature during physical activity. However, they also point out that sweat can be very salty and sometimes even stings when it gets in your eyes.

To better understand why sweat is salty, the twins head to a laboratory where they meet Professor Tim Walsh. He explains that sweat is made up of water, salt, and other minerals. When the body becomes overheated, sweat glands are activated, and they release a mixture of water and salt through tiny pores in the skin.

Next, the twins conduct an experiment to measure the salt content of their own sweat. They apply a patch to their arm that collects sweat over a period of time. They then compare the amount of salt in their sweat to the salt content of seawater, which is known to be very salty. Surprisingly, they find that their sweat is actually saltier than seawater.

The twins then meet a man who suffers from cystic fibrosis, a genetic condition that affects the body's ability to produce sweat. They explain that people with cystic fibrosis have very thick mucus in their lungs and other organs, which can lead to serious health problems. One of the ways to manage cystic fibrosis is through exercise, which helps to loosen the mucus and clear the airways. However, because people with cystic fibrosis produce very little sweat, they are at risk of overheating during exercise.

To demonstrate the importance of sweat for regulating body temperature, the twins conduct another experiment. They ask two volunteers to cycle on exercise bikes in a hot, humid room. One volunteer wears a special suit that prevents sweating, while the other wears a suit that allows them to sweat normally. After just a few minutes, the volunteer in the non-sweating suit becomes very hot and uncomfortable, while the other volunteer remains cool and comfortable.

The twins also investigate the role of sweat in body odour. They explain that when sweat mixes with bacteria on the skin, it can produce an unpleasant smell. To demonstrate this, they conduct an experiment using a special camera that can detect gases emitted by bacteria on the skin. They ask one volunteer to shower and wear clean clothes, while another volunteer skips their shower and wears the same clothes they wore the previous day. The camera detects a much higher concentration of bacteria on the second volunteer, explaining why they might have body odour.

Finally, the twins explore the cultural significance of sweat. They meet a group of Maasai warriors in Kenya who use sweat to communicate with each other. By sniffing each other's armpits, they can identify members of their own tribe and distinguish them from outsiders. They also visit a Russian bathhouse, where sweating is considered an important ritual that helps to cleanse the body and mind.

Overall, "Why is Sweat Salty" is an informative and entertaining episode that explores the many facets of sweat and its unique properties. Through a series of compelling experiments and demonstrations, the twins help to demystify this often-overlooked bodily function and shed new light on its many benefits.