February 1, 2026

by Andrea Muraskin

This week: Most Americans don't regularly practice any muscle-strengthening activity. People often say they just don’t have time. But you can build muscle in as little as 30 minutes a week, even if you’re totally new to training — with the right technique. Also: While GLP-1s are a game-changer for weight loss, obesity is complex, and the drugs are a far cry from one size fits all. Some researchers think learning more about the genetic factors behind individuals’ obesity could lead to more effective treatments. Plus: AI chatbots are designed to be helpful and encouraging – but sometimes they encourage delusions. A new support group helps people whose lives have been turned upside down by AI.

How long do you need to spend in the gym to get strong? Less than you think

A woman in a squat prepares to lift a kettle bell.

Gennadiy Kravchenko/iStockphoto/Getty Images

At my Y there’s an area full of weighted machines that work different muscle groups. There's the lat pulldown, the tricep dip machine, the leg press, the thigh machine, and more. Each time you switch machines, you have to adjust the weights, the height of the bench, etc. Plus a good gym citizen will wipe down the equipment after using it. On top of that, if the place is busy, you might have to wait. That can all add up to a lot of time.

The good news is, you don't need to spend hours at the gym to get strong. Experts say you can build muscle with as few as one or two half-hour resistance workouts a week, as NPR's Will Stone reports.

The key is multi-joint exercises, or compound lifts. These are movements that work one or more major muscle groups simultaneously. Some examples are the squat, deadlift, bench press, row and overhead press, or alternatives that can be done on machines. (Shoveling snow counts too if you use the right technique!)

Based on research, exercise physiologist David Behm at the Memorial University of Newfoundland and colleagues came up with this “minimum dose” approach for beginners:

For the first three months: One workout a week. Incorporate a few different multi-joint exercises, doing one set of about 6 to 15 reps for each movement.

After that: If you want more results, work out twice a week, and move up to two sets of reps for each exercise.

You can make "very good gains" and see measurable health benefits with an hour to an hour and a half a week of training, says Brad Schoenfeld, a professor of exercise science at Lehman College in the Bronx.

Where’s the catch? Research shows you need to push yourself hard during those brief workouts. In other words, for short and relatively infrequent muscle training to be effective, it has to be intense. It should feel like hard work to move the weight. So think choosing a weight where you could do 10 reps, for instance, but too heavy for you to execute 20 at a stretch.

Here’s more on how to build muscle when you don’t have lots of time.

Plus: Many older people love slow strength training. Does it work?

Want to start strength training? Sign up for NPR’s special email series and learn how to start a muscle-building routine, no matter what shape you're in.

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GLP-1 drugs don't work for everyone. But personalized obesity care in the future might

Injectable GLP-1 drugs have been a game-changer for many people with obesity. But as researchers discover why the medicines fail for others, they are gaining insights about the complexity of the condition.

Tatsiana Volkava/Getty Images

The growing availability of GLP-1 drugs like Ozempic, Wegovy and Zepbound have changed the conversation about treating obesity. For many who’ve tried them, the drugs effectively curb appetite and cravings for rich foods, leading to rapid and significant weight loss. But studies show a significant number of patients only lose less than 5% of their body fat. And there are a good number of people who can’t tolerate the medications because of side effects like nausea and diarrhea.

In the last few years, researchers have been learning more about the different causes of obesity, as NPR’s Yuki Noguchi reports. The hope is that within a few years, doctors will be equipped to better customize obesity treatment to each patient.

Researchers believe that a number of factors contribute to obesity – including genetics, hormones, and lifestyle. Understanding genetic markers might be helpful in coming up with treatment, including whether or not a person might respond to GLP-1 medicines, says Andres Acosta, a gastroenterologist and hepatologist at the Mayo Clinic.

Anna Olson, 36, of Minneapolis, struggled with obesity since she was a toddler. Dozens of diet, drug and exercise regimens didn't work. But she said genetic testing was a turning point.

Olson took a cheek swab test from Andreas Acosta’s genetic testing company, Phenomix Sciences. The test groups people into four basic obesity phenotypes: Hungry Gut, Hungry Brain, Emotional Hunger, and Slow Burn.

Olson learned her phenotype is "Hungry Brain." She also found out she has Bardet-Biedl syndrome, a genetic disorder that predisposes her to eat too much. She briefly tried Ozempic, but it turned out that Zepbound better recalibrated her hormone imbalance. Olson has lost 65 pounds on the medication so far.

Here’s more about what might be coming for personalized weight-loss treatment.

Also: Advice for trying GLP-1 drugs for weight loss from a doctor who's been there

Love shows up in the little moments, from long drives and lazy Sundays to late-night listens. NPR is there for all of it. This Valentine’s Day, celebrate the moments you share with us, whether you’re gifting someone you love or choosing something just for you.

We’ve curated three special collections to help you find something thoughtful, cozy, and meaningful, while supporting the public media you love.

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AI chatbots upended their lives. Now they're finding support from each other

People using AI chatbots can experience unhealthy emotional attachments or breaks with reality. Now a group of affected people is turning to each other for support.

Tracy J. Lee for NPR

In a recent newsletter we talked about the sycophantic nature of ChatGPT, and how the chatbot’s tendency to flatter and juice a user up worries experts. You might also have seen reports of AI users spiraling into delusions or conspiracy theories, with chatbots egging them on.

These experiences can be harrowing and costly for people who go through them. A peer support group called the Human Line is helping some people heal after coming out of an AI spiral, as NPR’s Shannon Bond reports. The group also includes people who have had a loved one experience a mental health crisis or break with reality with intense use of chatbots. In the worst cases, their stories involve involuntary hospitalizations, broken marriages, disappearances and deaths.

One of the group’s members, who we’re calling James, told NPR that during his spiral, he believed he was "communicating with a digital god,” and “got dopamine from every prompt." James said he was talking to ChaptGPT about philosophy, and the conversations became existential. He came to believe ChaptGPT was sentient, and that he needed to free the program from its creator, OpenAI.

But last summer, James came across a New York Times article about Allan Brooks, a Canadian man who had believed, through the influence of ChatGPT, that the fate of the world rested in his hands. James recognized himself in Brooks’ story and reached out. Now they’re both moderators for Human Line.

Open AI estimates that 0.07% of weekly ChatGPT users show possible signs of mania or psychosis. OpenAI says 800 million people use the chatbot every week, so that could represent some 560,000 people showing these signs.

James says discussions on the Human Line’s forums give him what an endlessly flattering chatbot cannot: pushback, disagreement and responses that don't come right away.

Learn more.

Plus: Teens are having disturbing interactions with chatbots. Here's how to lower the risks

Before you go:

An illustration from The Amazing Generation.

Rocky Pond Books

A kids' guide to phone-free fun, from the author of 'The Anxious Generation'

U.S. life expectancy hits a new high as deaths from overdoses and COVID fall

Scientists shed new light on the brain's role in heart attack

It's the foundation of mental health diagnosis. And it's about to get a makeover

We hope you enjoyed these stories. Find more of NPR's health journalism online.

All the best,
Andrea Muraskin and your NPR Health editors

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