Resistance training was associated with a substantially lower risk for type 2 diabetes (T2D), particularly when performed consistently over midlife and combined with adequate aerobic activity and limited sedentary television (TV) viewing, according to the results of a prospective analysis.

These findings support the inclusion of resistance training as a key component of lifestyle recommendations for diabetes prevention, Tianyue Zhang, MD, of Zhejiang University School of Medicine in Hangzhou, China, and Harvard T.H. Chan School of Public Health in Boston, and co-authors wrote in their paper published recently in JAMA Network Open.

In an email exchange with Medscape Medical News, Zhang emphasized that even relatively modest resistance training over midlife has benefits when practiced consistently. “For clinicians, this means it may be helpful to encourage patients not only to ‘walk more’ but also to add simple strength exercises at least once or twice per week and to maintain this habit over many years,” she said.

Long-Running Cohort Studies

The analysis was based on three major studies assessing lifestyle and health status: the Nurses’ Health Study, the Nurses’ Health Study II, and the Health Professionals Follow-Up Study (HPFS).

These three studies have run over decades with the support of the National Institutes of Health (NIH), giving researchers like Zhang and colleagues a valuable tool to study the effects of lifestyle choices.

“These cohorts are invaluable because habits like physical activity and sedentary behavior change over time, and chronic diseases such as [T2D] develop over many years,” Zhang told Medscape Medical News. “Without this kind of long‑term support, it would be very difficult to produce reliable evidence on how everyday lifestyle patterns truly affect long‑term health.”

Zhang said she and co-authors devised their study to address an evidence gap. While guidelines recommend resistance training for diabetes prevention, Zhang pointed out that little was known about the best long-term pattern of training, including how much should be done, how consistently, and its relationship with aerobic exercise and sedentary time.

In addition, earlier cohort studies usually had only one baseline measure of resistance training, so they could not fully capture changes over decades; using three long‑running cohorts with repeated measures “allowed us to answer these questions in much greater detail,” she said.

Analysis Details

A total of 143,715 adults with a mean age of 56.0 years (SD, 10.5) were included in the analysis. Study participants included adult healthcare professionals who had undergone at least three assessments of resistance training between 40 and 60 years of age.

Participants had been queried over the years about whether they did resistance training, such as weight lifting, using free weights or weight machines, along with questions about other activities such as walking, jogging, running, bicycling, tennis, swimming, and climbing flights of stairs.

Compared with no resistance training, engaging in 2 or more hours per week of resistance training was associated with a lower T2D risk (hazard ratio [HR], 0.73; 95% CI, 0.66-0.81), Zhang and co-authors reported.

Participants who engaged exclusively in upper limb resistance training were at lower risk for T2D (HR, 0.75; 95% CI, 0.69-0.83), as were those performing both upper and lower limb training (HR, 0.83; 95% CI, 0.78-0.88) than participants with no training.

In a joint analysis, participants who engaged in resistance training and met the recommended aerobic activity and limited their TV viewing had the lowest risk for T2D (HR, 0.38; 95% CI, 0.34-0.42) compared with patients who met none of these recommendations.

Limitations of the study include the reliance on self-reported data on training, Zhang and co-authors wrote. They also noted the limitations of relying on large long-term studies that recruited people in medical professions, with 96.7% of participants included in this analysis being White.

Bolstering the Case for Patients

Asked to comment, JoAnn E. Manson, MD, DrPH, chief of the Division of Preventive Medicine at Brigham and Women’s Hospital in Boston, said the new paper adds to arguments clinicians can make in advising patients to incorporate resistance training into their daily lives.

Manson was not involved in the current project, but she has published previous research with similar findings. In a 2017 paper in the journal Medicine & Science in Sports & Exercise, Manson and co-authors reported that women engaging in any strength training experienced a reduced rate of T2D of 30% (HR, 0.70, 95% CI, 0.61-0.80) when controlling for time spent in other activities and other confounders compared with women who reported no strength training.

For that paper, Manson and co-authors analyzed data from the Women’s Health Study, another major long-term research project examining how diet, medications, and lifestyle may prevent or lessen the impact of cancer and chronic diseases.

Manson has long been a leader in this field of research. She was one of the top investigators for the Women’s Health Initiative and the principal investigator for the cardiovascular component of the Nurses’ Health Study.

These large studies have produced many papers reporting on how diet and certain medications may raise or lower risk for disease, but there’s been surprisingly little research on the specific effects of strengthening activities, said Manson.

“The research is sparse,” she said. “There has been some research on strength training, but it’s been limited. This helps fill a gap in the evidence base for these kinds of recommendations.”

“The more research there is on this subject, the clearer the physical activity guidelines can be,” she added. “This becomes so important for older adults because there are higher risks of loss of lean body mass and sarcopenia, as well as increased risk of [T2D] and cardiovascular disease.”

NIH grants supported the studies from which data were drawn for this analysis: the Nurses’ Health Study, the Nurses’ Health Study II, and the HPFS. Additional support came from grant 311109/2023-3 from the National Council for Scientific and Technological Development for one of the authors, Leandro F.M. Rezende, ScD.

None of the authors or Manson reported any relevant financial disclosures.