For many women with breast cancer, the very treatment that saves their lives can also bring fatigue, loss of muscle mass, emotional strain and other daunting obstacles.

A new study shows that exercise during chemotherapy does more than rebuild strength — it measurably improves quality of life while treatment is underway, helping women feel better physically, emotionally and mentally during one of the most demanding chapters of care.

Led by researchers at Sylvester Comprehensive Cancer Centre, part of the University of Miami Miller School of Medicine, the findings come from a large meta-analysis published in The Lancet Healthy Longevity and synthesise results from more than two dozen studies of women receiving chemotherapy for breast cancer.

Modern breast cancer treatment has dramatically improved survival rates.

But alongside those gains, clinicians and researchers are increasingly focused on how patients feel during treatment — their energy, mood, mobility and sense of well-being.

“Chemotherapy places stress on every system in the body,” said LaShae D.Rolle, MPH, CPH, lead author of the study, a predoctoral fellow conducting research at Sylvester.

“Quality of life becomes a central outcome during treatment, not something to consider only after it ends.”

Exercise has long been recommended after cancer treatment, but the evidence for exercising during chemotherapy has been more mixed.

That uncertainty often leaves patients unsure whether movement will help or hurt when they are already feeling depleted.

The new analysis helps provide clarity. The Sylvester-led team analysed 21 randomised controlled trials, representing more than 3,000 women undergoing chemotherapy for breast cancer.

Rather than focusing on a single type of exercise, they examined a wide range of interventions, including:

• Aerobic activity, such as walking or cycling
• Strength or resistance training
• Combined programmes that incorporated both

Across these studies, women who participated in structured exercise programmes experienced significant improvements in quality of life compared with those receiving standard care alone.

The benefits were consistent across physical, emotional and mental health domains for quality of life.

“It’s not about pushing through exhaustion,” Rolle said.“It’s about finding movement that supports the body while it’s under strain.”

Importantly, the study showed that no single type of exercise emerged as ‘the best'. Aerobic exercise, strength training, and combined programmes all led to meaningful improvements in quality of life.

That flexibility is key during chemotherapy, when energy levels can fluctuate day to day.

“Exercise during treatment shouldn’t feel rigid or intimidating,” said Tracy Crane, Ph.D., RDN, co-author of the study, co-leader of the Cancer Control Programme and director of lifestyle medicine, prevention and digital health at Sylvester and associate professor in the Division of Medical Oncology at the Miller School.

“This study reinforces that patients can benefit from many different forms of movement, as long as the approach is safe, personalised, and realistic,” she said.

Notably, the study focused exclusively on women undergoing active chemotherapy, not survivors months or years after treatment. That distinction matters.

Exercising during chemotherapy comes with unique challenges, including variability in symptoms, treatment schedules, and physical capacity.

The findings support existing clinical guidelines that encourage physical activity during treatment, with appropriate supervision and adjustments.

“This evidence gives clinicians greater confidence to recommend exercise during chemotherapy,” Rolle said.

“And it reassures patients that movement, at the right level, can be part of their care.”

As cancer care continues to evolve, studies like this help integrate supportive strategies alongside medical treatment — not as extras, but as essential components of whole‑person care.

“This work helps move exercise from the margins into the mainstream of oncology care,” Crane said.

“It shows that any form of exercise during chemotherapy has a positive impact on quality of life for women being treated for breast cancer.”

Source: University of Miami Miller School of Medicine
DOI: 10.1016/j.lanhl.2026.100819