Q & A:High-Intensity Resistance Training for Recovering AN Patients?

Q. I’ve read that low-intensity exercise is safe for recovering anorexia nervosa (AN) patients, but is more strenuous exercise ever advisable? (GM, Fort Lauderdale, FL)

A. Fat, bone, and muscle tissues are more seriously affected in patients with AN compared with other eating disorders. Relative immobilization during treatment only adds to this. Incorporating regular physical activity or exercise programs into treatment for patients with restrictive-type anorexia nervosa (AN-R) is still controversial. Perhaps because excessive or driven exercise is often encountered as an eating disorder symptom, clinicians have often been very reluctant about exercise in people recovering from AN. Yet it is not clear that a “lifelong abstinence” model make sense in this context. A group at Texas Tech University, Lubbock, TX, recently had excellent early results with a high-intensity resistance training program for a small group of adolescents with restrictive-type AN (Int J Eat Disord 2014; 47601).

Thirty-six female patients with DSM-IV AN-R, who were 16 years of age or younger and with BMIs greater than 14.0, were randomly assigned to an intervention group or to a control group. Before the 8-week intervention program began, all the teens underwent a familiarization period, to minimize any learning effect that could result technical or neuromuscular improvement on the strength and agility tests. The main part of the exercise sessions involved 2 to 3 sets of 5 to 8 repetitions of the exercises used to assess strength. Body weight, BMI, muscular strength, and agility and were evaluated before the exercise sessions, and at the end of the program and at 4 weeks after the training program.

Resistance exercise produced significant improvement in strength and was well-tolerated. For example, lower body strength increased an average of 52% (leg press) and upper body strength increased an average of 37% to 41% (measured by lateral row and bench-press, respectively).

Four weeks after the intervention period, there had been a small loss of the gains obtained in strength-related variables (an average loss of 15% in the upper body and 7% in the lower body). Just as in the general population, AN-R patients lost muscle strength after the training program ended but some improvements persisted. The intervention was well received: 4 patients in the control group dropped out (1 was hospitalized and 1changed care centers; 2 declined to continue). Four persons in the intervention group also dropped out (1 was hospitalized, 1 discharged, and 2 changed care centers).

Dr. Maria Fernandez-del-Valle and her colleagues argue that exercise programs should target muscular mass and functional recovery. In AN-R, an appropriate exercise program would control caloric intake, avoid high-level exercise, focus on muscle recovery, would be intense and frequent enough to induce adaptations, be individualized and closely supervised. Finally, patients should be monitored after the initial exercise programs are completed.

Much remains to be learned about prescribing exercise for AN-R patients, including the appropriate dosage and duration of exercise and the beset mixture of types of exercise. Of particular interest is the possibility that exercise could help address osteoporosis. Due to the epidemiologic history of AN (with AN becoming much more common in the last third of the 20th century),relatively few people with AN-associated osteoporosis have yet reached their 60s, 70s, or 80s Because of that, the true magnitude of the burden of osteoporosis in this group is not yet known, but may be very substantial. If so, effective treatment approaches—including perhaps exercise—will be badly needed.

— SC