Hair

Big hair? Bald? How much difference your hair really makes to keep you cool or warm

June 15, 2023

When humans moved from living in the jungle to the savannah, they needed to walk and run long distances in the sun. This meant they needed a way to handle the increased body temperature that comes with physical activity in the heat.

Sweating is the best way to lose heat and cool down, but the presence of hair reduces sweating and heat loss from the skin. So humans evolved to lose body hair to be better adapted to exercising in the heat. Fewer hair follicles in our skin made room for more sweat glands. This made our skin optimal for sweat evaporation – and the heat loss that goes with it – to keep us cool.

Environment, Environmental Health, Global Health

Climate Crisis Is on Track to Push One-Third of Humanity Out of Its Most Livable Environment

June 7, 2023

Climate change is remapping where humans can exist on the planet. As optimum conditions shift away from the equator and toward the poles, more than 600 million people have already been stranded outside of a crucial environmental niche that scientists say best supports life. By late this century 3 to 6 billion people, or between a third and a half of humanity, could be trapped outside of that zone, facing extreme heat, food scarcity and higher death rates, unless emissions are sharply curtailed or mass migration is accommodated.

Diet, Fitness, Nutrition, Weight Loss

It’s time to bust the ‘calories in, calories out’ weight-loss myth

June 7, 2023

One reason the simple “calories in, calories out” formula is not so simple is our bodies don’t consume every calorie the same way. What’s shown in your calorie counter is not what’s actually absorbed in your body. Different calorie sources also have different effects on our hormones, brain response and energy expenditure, changing how we respond to and manage our food intake.

Cytomegaloviru, Infectious Disease, Pregnancy

Cytomegalovirus lies dormant in most US adults and is the leading infectious cause of birth defects, but few have heard of it

June 1, 2023

“Why didn’t anyone tell me about this virus?” is a frequent response I hear from parents upon learning their newborn is infected with cytomegalovirus, or CMV. Although more than half of the U.S. population will be infected with CMV by the age of 40 and the disease is common worldwide, few people have ever heard of it.