The finding may come as a surprise because many people assume that shedding excess weight naturally makes it easier to move more. However, researchers found the opposite trend among people taking these medications.

Weight Loss Drugs and Muscle Health

The medications studied belong to a class known as glucagon-like peptide-1 (GLP-1) receptor agonists. This group includes semaglutide (Ozempic and Wegovy), tirzepatide (Mounjaro and Zepbound), liraglutide, and dulaglutide.

While these drugs can be highly effective for weight loss, they reduce more than just body fat. They can also contribute to a loss of lean muscle mass, making physical activity especially important for maintaining strength and overall health.

Protecting muscle is a key part of healthy weight loss, explained study leader Sajana Maharjan, M.D., of HSHS St. John’s Hospital in Springfield, Illinois.

Fitbit Data Showed Activity Declines

To investigate how activity levels changed after starting treatment, researchers analyzed data from the National Institutes of Health’s All of Us Research Program, which combines electronic health records with Fitbit activity data.

The study began with 1,950 adults with obesity who started a GLP-1 medication. Of those, 753 participants had enough wearable-device data to be included in the final analysis. Most were women (78.6%), and the average age was 52.7 years.

Researchers compared physical activity before and after participants began taking the medications. They focused on daily step counts and minutes of moderate-to-vigorous physical activity (MVPA).

Fewer Steps and Less Exercise

The results showed a clear decline in movement after treatment began.

Average daily step counts fell from 5,047 to 4,487 steps per day. Time spent in moderate-to-vigorous physical activity (MVPA) also dropped, decreasing from 28 minutes to 22 minutes per day.

The largest decreases were seen in men and in people who reported joint or muscle pain. Factors such as age, heart failure, and a previous stroke did not alter the findings.

Importantly, the researchers found no evidence that losing weight with these medications led people to become more physically active.

Exercise Cannot Be an Afterthought

“While many assume that weight loss leads naturally to increased physical activity, our study suggests otherwise. The findings in our study reinforce that exercise cannot be optional for people taking these medications. People need targeted interventions that encourage physical activity alongside medication for obesity,” Maharjan said.

According to the researchers, this is the first large study to use wearable fitness tracker data to examine physical activity patterns among adults taking GLP-1 receptor agonists.

A single degree Celsius equals 1.8 degrees Fahrenheit.

The study also demonstrates that synthetic aperture radar (SAR) can automatically and consistently monitor glaciers and their snowlines throughout the year. Traditionally, snowlines are usually measured only near the end of the melt season using optical instruments.

Researchers found that SAR provides more dependable data than conventional surface-based optical methods.

The findings were published in Nature.

The study was led by Albin Wells, a recent Ph.D. graduate from Carnegie Mellon University. Co-authors include Carnegie Mellon assistant professor David Rounce and Mark Fahnestock of the University of Alaska Fairbanks Geophysical Institute. Rounce previously worked at the Geophysical Institute as a postdoctoral fellow and research associate.

Tracking Glacier Melt From Space

The research team used radar observations to measure glacier “melt days.” A melt day may represent a full 24-hour period when an entire glacier is melting, or it can consist of several days during which melting occurs across different portions of the glacier until the total affected area equals the glacier’s full surface.

An increase in melt days indicates that the melt season is becoming longer, which contributes to greater overall ice loss.

Using data from Europe’s Sentinel-1 radar satellites, the scientists monitored seasonal changes on nearly every Alaska glacier larger than about half a square mile between mid-2016 and 2024.

Synthetic aperture radar operates by transmitting microwave pulses from a moving satellite or aircraft toward Earth’s surface and then combining the returning signals into detailed images. Because it does not rely on sunlight, SAR can collect data through clouds and in darkness.

Sentinel-1 revisits the same location every 12 days and covers more than 3,000 glaciers across Alaska.

Heat Waves Accelerate Snow Loss

The researchers also discovered that short-term heat waves can dramatically reduce the snow cover that protects glaciers. During unusually warm periods, glaciers lost up to 28% more protective snow than they do in typical years. This percentage applies at the scale of individual mountain ranges and does not necessarily affect every glacier equally within those regions.

“Our ability to quantify these changes is really important,” Wells said. “Melt extents and snowlines are proxies for glacier mass balance.”

Glacier mass balance refers to the difference between how much snow and ice a glacier gains and how much it loses over time.

“These correlations with temperature begin to give a sense for how much melt or snowline retreat we can anticipate under future, warmer climates across the region,” Wells said.

A snowline marks the boundary between a glacier’s accumulation zone, where snow builds up and adds mass, and its ablation zone, where melting removes snow and ice.

Why Radar Outperforms Optical Monitoring

Glaciologists generally rely on optical instruments to evaluate snowlines near the end of the melt season, usually in late summer or early autumn.

“In optical data, the snowline can be really hard to observe,” Fahnestock said. “If you’re a day late taking your picture, it might have snowed on the entire glacier, and you can’t see where the bare glacier ice is down below and where the snow and firn is above.”

Firn is partially compacted granular snow found near the upper portions of glaciers. Over time, it can gradually transform into glacier ice.

According to Fahnestock, optical observations can be affected by changing lighting conditions, shadows, cloud cover, and variations in whether firn appears clean or dirty.

SAR avoids many of those limitations and can provide regular snowline measurements throughout the melt season.

“What Albin has done is operationalize the tracking of surface conditions on the glaciers in a way that can be applied anywhere,” Fahnestock said.

The 2019 Alaska Heat Wave

The researchers closely examined an intense Alaska heat wave that lasted from June 23-July 10, 2019. The event affected every glaciated region of the state except the Brooks Range.

For nearly two weeks, temperatures at many locations ran 20 to 30 degrees above average. Several all-time records were broken, including a reading of 90 degrees Fahrenheit at Ted Stevens Anchorage International Airport. Typical summer highs in Anchorage are usually in the mid-60s.

According to the study, the extreme heat pushed glacier snowlines nearly 350 feet higher in elevation. In an average year, snowlines would not reach those elevations until roughly two months later.

As a result, bare ice and firn remained exposed for longer periods, increasing overall ice loss.

The authors write that this highlights “the sensitivity of glaciers to short-term climatic variability.”

Coastal and Inland Glaciers Behave Differently

The study also identified consistent differences between glaciers located on the coastal side of mountain ranges and those farther inland.

Wells said the number of melt days varied between the two groups, suggesting they respond differently to environmental conditions even though many are losing ice at broadly similar rates.

“This is an important finding,” Wells said, “because it corroborates prior knowledge that glaciers in Alaska on the coastal side of mountains have more melt in summer and more accumulation in winter than those on the continental side of the ranges.”

Many industrial activities depend on separating different substances from one another. These separation processes are essential for tasks such as drug purification, textile dye treatment, and food production. Yet they are also among the most energy-intensive operations in manufacturing, accounting for roughly 40% to 50% of global industrial energy consumption.

Most facilities still rely on traditional approaches such as distillation and evaporation. While effective, these methods require large amounts of energy and contribute significantly to carbon emissions. Membrane-based filtration is generally considered a cleaner alternative, but conventional polymer membranes often contain pores of uneven size. Over time, those pores can change shape or degrade, reducing performance and limiting their usefulness in demanding industrial environments.

Nature-Inspired POMbranes With One-Nanometer Pores

“To address these limitations, we engineered a new class of ultra-selective, crystalline membranes called “POMbranes,” which contain pores that are about one nanometer wide, thousands of times thinner than a human hair,” said Dr. Shilpi Kushwaha, Senior Scientist at CSMCRI.

The new membranes draw inspiration from biological systems such as aquaporins, which regulate the movement of molecules through precisely sized channels. To achieve this level of control, the researchers used polyoxometalate (POM) clusters. Each cluster contains a naturally occurring opening that is exactly 1 nanometer wide and remains permanently stable.

According to Ms Priyanka Dobariya, a CSMCRI research scholar and co-first author of the article, “These POMs are tiny, crown-shaped metal clusters that have a permanent, perfect hole in their centre that does not change or lose shape, which is the biggest hurdle with traditional plastic filters.”

Building an Ultrathin Molecular Sieve

Creating a practical membrane required arranging billions of these tiny ring-like structures into a continuous, defect-free layer. To accomplish this, the researchers attached flexible chemical chains to the POM clusters.

When the modified clusters were placed on water, they naturally spread out and organized themselves into a large-area ultrathin film. By changing the length of the attached chains, the team was able to control how closely the clusters packed together.

“This forced molecules to cross the membrane through the only open path, the one-nanometer holes built into each cluster, allowing the membrane to act like a high-tech sieve,” added Dr. Raghavan Ranganathan, Associate Professor at IITGN’s Department of Materials Engineering.

Dr. Ranganathan and Mr. Vinay Thakur, a PhD scholar at IITGN and the co-first author of the article, also carried out molecular-level simulations that revealed how the membranes perform their filtering function.

Nearly Ten Times Better Separation Performance

Testing showed that the membranes could distinguish between molecules that differ by only 100-200 Daltons, a level of precision that is extremely difficult to achieve with conventional polymer membranes.

According to Dr. Ketan Patel, Principal Scientist at CSMCRI, this capability could create new opportunities for more sustainable manufacturing processes.

“Our membranes show almost ten times better separation performance compared to existing technologies, while remaining flexible, stable, and scalable,” he said.

“Additionally, these membranes are flexible, stable across different acidity levels (pH ranges), and can be manufactured in large sheets. This combination is essential if the membranes are to be adopted widely in industry.”

Potential Benefits for Textiles and Water Recycling

The technology could be particularly valuable for India’s textile and pharmaceutical industries, both of which play major roles in the country’s economy.

India’s textile and apparel sector contributes more than 2.3% of GDP and represents approximately 13% of industrial production. The domestic market is currently valued at $160-225 billion and is expected to expand to $250-350 billion by 2030.

Textile dyeing and finishing operations generate large amounts of contaminated wastewater, making dye removal and water reuse ongoing challenges. The new membranes could selectively remove dye molecules while allowing water to be recycled, reducing both freshwater demand and chemical waste. This advantage is especially important as India’s wastewater treatment market continues to grow.

Applications in Pharmaceutical Manufacturing

The membranes could also benefit pharmaceutical production, where highly accurate separations are critical for product quality and manufacturing efficiency.

“Processes like drug purification and solvent recovery are both energy-intensive and quality-sensitive,” noted Mr. Vinay Thakur. “Highly selective membranes such as these can lower energy use while maintaining the stringent standards required in pharmaceutical production.”

A Platform Technology for Sustainable Manufacturing

Researchers describe the new POMbranes as a versatile platform technology. Their adjustable structure, high selectivity, and ability to withstand harsh chemical environments make them suitable for a broad range of industrial separation tasks, from wastewater treatment to advanced chemical manufacturing.

As industries increasingly look for technologies that combine efficiency, durability, and sustainability, molecularly engineered membranes may become an important part of next-generation manufacturing systems. By applying a principle commonly found in biology, precise control at the molecular scale, and adapting it into a scalable materials technology, the researchers have demonstrated how nature-inspired design can help solve major industrial challenges.