Every week, we bring you a roundup of the latest health and wellness news to hit the wire. This week, we look at what hot yoga does and doesn’t do for you, what’s really keeping us awake at night, and the link between midlife stress and cognitive decline in women. 

You don’t need a heated room to reap the benefits of yoga

While it may feel good to leave a yoga class drenched in sweat, new research in Time suggests that you don’t need to crank up the heat to get the benefits.

A study of Bikram yoga, which features 26 postures and breathing exercises conducted in rooms heated to 105 degrees, found that while it did boost vascular health, those results were probably more about the postures than the heat.

The study, published in the journal Experimental Physiology, followed 52 previously sedentary adults. Of those, 19 went to Bikram classes three times a week, and 14 went to regular yoga classes in a 73-degree room. A control group of 19 people did not do yoga at all.

After 12 weeks, researchers assessed everyone’s vascular health by looking at endothelial function, or the ability of blood vessels to dilate in response to greater blood flow. Both groups saw changes that indicated a lower risk of heart disease, while the control group did not.

One note: The hot yoga group did see a small but still significant reduction in body-fat percentage compared to the room-temperature group, which was surprising to researchers given that past studies did not show Bikram to be an effective workout for weight loss. And other research has suggested that the high heat and humidity may raise the body’s internal temperature and heart rate to unsafe levels.

So if dripping in Downward Dog isn’t your thing or you can’t stand the heat, know that regular yoga classes are still doing your body good.

The biggest enemies of sleep

If you’ve cut out that iced coffee in the afternoons to get better sleep but are still popping open a beer after work, you’re doing it all wrong, according to a new study in Healthline.

When researchers at Florida Atlantic University—in conjunction with Brigham and Women’s Hospital, Harvard University, Emory University, the University of Mississippi Medical Center and the National Institutes of Health—studied the evening habits of 785 African-American adults over a combined 5,164 days, they found that alcohol and nicotine (either from smoking or vaping) disrupted sleep far more than caffeine.

Using trackers and sleep diaries to measure shut-eye, researchers found that those who used nicotine or alcohol within four hours of going to bed felt the largest impact on their sleep cycle, with nicotine being the hardest on those with insomnia, resulting in 40 minutes less sleep.

There was little correlation between coffee consumption within four hours of bed and sleep difficulties.

The research was important for two more reasons. It studied African-Americans who are not only underrepresented in research, but also tend to struggle more with sleep than some other groups. And the research also included participants who didn’t really think they had problems with sleep, rather than chronic insomniacs.

The take-away, sleep experts say, is don’t consume nicotine or alcohol after dinner for optimal sleep, and if you need a jolt of java to fight the midafternoon slump, by all means, enjoy.

Is this why more women get dementia?

New research in this Yahoo article shows that stressful midlife experiences are more likely to negatively affect a women’s memory and increase her risk of cognitive decline later in life.

The research on 337 men and 572 women conducted by Johns Hopkins Medicine between 1982 and 2004 tracked asked participants over different time periods about whether they had experienced traumatic events such as physical attacks, natural disasters or threats or stressful life experiences such as divorce, death of a loved one, severe injury or job loss.

At the third and fourth visits, they were asked to complete a learning and memory test. Those women who experienced a greater number of stressful life experiences in midlife showed greater declines in the memory test. The same decline was not seen in those who had experienced traumatic events, researchers say, possibly because longer-term stress of the type experienced during a divorce has a more negative impact on brain functioning than distinct traumatic events. A similar association between stress and dementia was not found in men.

Researchers say that when stress hormones such as cortisol remain elevated for long periods, it isn’t good for the hippocampus, or the seat of the memory in the brain.

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