Every week, we’re bringing you a roundup of the latest health and wellness news to hit the wire. This week, we look at the quickest effective strength session, bad news about probiotics and the stress we’re all feeling.

Stronger in one set

Good news: If you find yourself checking out or rushing through your weight-training sets, according to this New York Times article, a new study found that you may be able to get away with one short set of each exercise and still improve muscle strength and size.

The traditional advice has been to complete three sets of eight to 12 repetitions of each movement, whether it’s a biceps curl or overhead press, with the muscle so tired at the end of each set, you feel like you can’t go on.

This new research, conducted by researchers at Lehman College in the Bronx, New York, and published in Medicine & Science in Sports & Exercise, tested 34 men who were already doing regular resistance training. The researchers measured the participants’ strength, endurance and size, and then they assigned them to different doses of a basic weight-training routine three times a week for eight weeks.

One group did five sets of each move, with 90 seconds of rest in between sets, resulting in 70 minutes of time at the gym; the second did three sets, finishing in about 40 minutes; and the last group had to finish only one set, getting them out the door in just 13 minutes.

After two months all were stronger, with the strength improvements being virtually the same no matter how many sets they did, and all had similar endurance for completing reps. Only the size of the muscles differed, with those doing five sets having greater muscle mass than those doing three sets or one.

The key to success, says Brad Schoenfeld, the study’s lead author, is lifting enough weight to be totally exhausted after each eight- to 12-rep set—something most people don’t actually do.

Do probiotic supplements really help?

It seems like everyone is popping a probiotic these days, hoping to improve their digestive and overall health. But new research suggests that one size of these supplements doesn’t fit all and that we may actually be doing more harm than good.

Looking inside the human gut with endoscopies and colonoscopies, researchers from the Weizmann Institute of Science in Israel found that many people’s digestive tracts prevent standard drugstore probiotics from colonizing them. Furthermore, they found that taking probiotics after antibiotics could actually delay the repopulation of normal gut bacteria and gut gene expression.

After consuming generic probiotic strains for two months, the scientists found that some of the group’s GI tracts were colonized and probiotics resided in the gut, while others, so-called resisters, actually expelled them.

And in a second study, those receiving probiotics after a course of antibiotics actually took longer for their gut microbiome and gut gene expression to return to normal, compared with a couple of days for those receiving a fecal microbiome transplant of their own bacteria from before the antibiotics.

The studies suggest that probiotics are for many people useless and that any treatments should be tailored to the individual.

It’s not just you—we’re all more stressed

If you’ve found your emotions swinging from sadness to stress to worry more times in the last year, welcome to the club.

Gallup’s Negative Experience Index—a measure of how many people experienced worry, stress, sadness, anger or pain on the day before the survey—reached its highest point since 2006, according to Time, and the Global Positive Experience Index declined for the second year in a row.

“Collectively, the world is more stressed, worried, sad and in pain today than we’ve ever seen it,” Gallup Managing Editor Mohamed Younis wrote in the report, which was based on more than 154,000 interviews with adults across the globe.

Who was the happiest? Paraguay and other Latin American countries topped the good- vibes list. The U.S. also was among those with the most positive experiences yet landed in the middle of the global pack for negative experiences because of Americans’ high levels of stress, anxiety and depression.

Photo credit: Anthony Tran, Unsplash