Study Finds the Weekly Sweet Spot for Strength Training Is Lower Than Expected

A long-term study published in the British Journal of Sports Medicine suggests that people may not need hours in the gym to gain major health benefits from resistance training. Tracking more than 147,000 participants, the researchers found that 90 to 120 minutes of strength work per week appeared to be the optimal range, especially when combined with aerobic exercise.

The study analyzed data from three large U.S. cohorts of health professionals followed for up to 30 years. Participants, 31,540 men and 115,834 women, had a median age of 54 at the start of follow-up. Over time, 35,798 participants died. About 46% reported doing some strength training, and 74% said they exceeded 150 minutes of moderate aerobic activity per week.

After adjusting for other factors, strength training was linked to a lower risk of death from any cause. The lowest risk was seen among those who trained 90 to 119 minutes weekly, with a 13% lower risk of all-cause mortality, 19% lower risk of cardiovascular death, and 27% lower risk of neurological death. Dr. Nitzan Anou of Maccabi Healthcare Services called it an unusual study that identifies a practical “sweet spot” and showed that “more is not always better.”

The biggest benefit appeared among people who combined high levels of aerobic exercise with 60 to 119 minutes of strength training a week, a group with a 45% lower death risk than the most sedentary participants. For cancer mortality, the strongest association showed up at lower doses of strength training, 1 to 29 minutes a week cut risk by 21% and 30 to 59 minutes by 18% for exercise-related cancers. Anou stressed that the findings show correlation, not causation, and noted limits including self-reported data, lack of intensity measures, and a study population made up mostly of older U.S. health professionals.