For a fixed amount of exercise, increasing exercise intensity consistent with consensus recommendations eliminated CRF nonresponse. Low-intensity exercise may not be sufficient to improve CRF for a substantial proportion of sedentary obese adults.

Fixed amounts of exercise independent of exercise intensity resulted in similar reductions in abdominal obesity. Reduction in 2-hour glucose level was restricted to high-intensity exercise.

AimTo determine the separate effects of exercise amount and intensity on the rate of response for glucose and insulin variables, where rate of response was defined as the number of individuals with improvement in glucose and insulin values that was beyond the day-to-day variability of measurement.MethodsParticipants were 171 sedentary, middle-aged abdominally obese adults who completed a 24-week intervention. Participants were randomly assigned to (1) no-exercise control (n = 51), (2) low-amount, low-intensity exercise (LALI, n = 38), (3) high-amount, low-intensity exercise (HALI, n = 52), or (4) high-amount, high-intensity exercise (HAHI, n = 30). Two-hour glucose, insulin area under the curve (AUC), and fasting insulin were measured during a 2-hour, 75g oral glucose challenge. The day-to-day variability for these measures was calculated to be ±2.2 mmol/L, ±940.2 pmol/L, and ±38.9 pmol/L, respectively.ResultsAt 24 weeks, the number of nonresponders for 2-hr glucose was 98.0%, 86.8%, 94.2%, 86.7% in the control, LALI, HALI, and HAHI groups, respectively. The number of nonresponders for insulin AUC was 88.0%, 75.7%, 75.0%, 80.0% in the control, LALI, HALI, and HAHI groups, respectively. The number of nonresponders for fasting insulin was 88.2%, 84.2%, 84.6%, 93.3% in the control, LALI, HALI, and HAHI groups, respectively. The rate of response was not different between control and any of the exercise groups for any measure (p>0.05).ConclusionThe improvement in glucose and insulin measures did not exceed the day-to-day variability of measurement for approximately 80% of the participants independent of exercise amount or intensity.

Objective To determine the effects of exercise amount (kilocalories per session) and intensity (percent of maximal oxygen consumption [% VO2peak]) on adipose tissue (AT) and skeletal muscle (SM) in adults with abdominal obesity. Methods Participants (n = 103; 52.7 ± 7.6 years) were randomized to the following groups: control; low‐amount, low‐intensity exercise (180 kcal/session [women] and 300 kcal/session [men] at 50% VO2peak); high‐amount, low‐intensity exercise (HALI; 360 kcal/session [women] and 600 kcal/session [men] at 50% VO2peak); or high‐amount, high‐intensity exercise (HAHI; 360 kcal/session [women] and 600 kcal/session [men] at 75% VO2peak) for 24 weeks. Activities of daily living were measured by accelerometry. Magnetic resonance imaging was used to measure tissue mass. Results Reduction in all AT depots was greater in the exercise groups compared with control (P < 0.002); however, there were no differences between exercise groups (P > 0.05). Visceral and abdominal subcutaneous AT reduction was uniform across the abdomen. Total SM mass did not change with exercise compared with control (P = 0.32). However, while lower‐body SM mass was maintained (P = 0.32), upper‐body SM mass in the high‐amount, high‐intensity and the high‐amount, low‐intensity groups was reduced compared with controls (P < 0.008). Conclusions In adults with abdominal obesity, substantial reductions in total, abdominal subcutaneous, and visceral AT with a preservation of total SM mass were observed independent of exercise amount or intensity.

During a descent movement that simulates fall arrest, the energy-absorbing capacity of the upper extremities in older women is nearly half that of young women. Absorbing the full energy of a fall in the upper extremities is a challenging task even for healthy young women. Strengthening of upper extremity muscles should enhance this ability and presumably reduce the risk for injury to the hip and head during a fall.