During the past several years, many studies have highlighted the health value of strength training for aging adults. Research at the University of Maryland has shown that strength training is effective for improving glucose metabolism, increasing bone mineral density, and speeding up gastrointestinal transit. Studies at Tufts University have demonstrated that strength exercise adds lean tissue, increases resting metabolism, and reduces arthritic discomfort. Extensive work at the University of Florida has shown that strength training increases low back strength and alleviates low back pain.

While all of these health and performance factors are important, perhaps the most compelling concerns for most seniors are the three "Bs"-body weight, blood pressure, and body composition.

Most senior men and women are concerned about getting soft, gaining weight, and elevating their blood pressure. They have already discovered that dieting doesn't produce permanent weight loss and that walking isn't always effective for firming muscles. Quite true. Unfortunately, many seniors are afraid to try strength training, because they've heard that it can increase both their body weight and their blood pressure. Untrue.

Several small-scale studies have shown that strength exercise is effective for decreasing body weight, increasing lean weight, and reducing resting blood pressure. In addition, strength training results in a higher resting metabolic rate and greater daily energy utilization.

But what specific changes can seniors expect from a basic program of strength exercise? We recently analyzed data on 1,132 men and women who completed the South Shore YMCA basic fitness program. All of the participants performed 25 minutes of strength exercise and 25 minutes of endurance exercise, two or three days per week for a period of eight weeks.

The strength-training program included the following Nautilus exercises: leg extension, leg curl, leg press, chest cross, chest press, super pullover, lateral raise, biceps curl, triceps extension, low back, abdominal curl, neck flexion, and neck extension. Each exercise was performed for one set of eight to 12 repetitions, at a slow movement speed (2 seconds lifting and 4 seconds lowering) and through a full range of motion. Resistance was increased by approximately five percent when 12 repetitions were completed.

The endurance-training program involved walking on a treadmill and stationary cycling. Participants exercised at about 70 to 75 percent of their maximum heart rate, and progressively increased their training time to 25 minutes of continuous aerobic activity.

The basic fitness program was offered in a separate and carefully supervised exercise room. Classes were held almost every hour throughout the day, and typically had six participants with two instructors. The class members were assessed for body weight, body composition, fat weight, lean weight, systolic blood pressure, and diastolic blood pressure before and after the two-month training period.

Weight and Body Composition
The 1,132 basic fitness program participants included 238 young adults (21 to 40 years), 553 middle-aged adults (41 to 60 years), and 341 senior adults (61 to 80 years). As shown in Table 1, all three age groups started the program with similar body weights (172.7 to 179.9 lb.) and percent fat readings (25.6 to 27.2 percent). The body weight and body composition changes were comparable for all age groups.

As presented in Table 1, the 21-to-40 year-olds lowered their body weight by 2.6 pounds and their percent fat by 2.3 percent. The 41-to-60-year-olds decreased their body weight by 2.0 pounds and their percent fat by 2.1 percent. The 61-to-80-year-olds reduced their body weight by 1.7 pounds, and their percent fat by 2.0 percent.

Changes in fat weight and lean weight were also similar for the three age groups. The 21-to-40-year-olds lost 4.9 pounds of fat weight and added 2.3 pounds of lean weight.

The 41-to-60-year-olds lost 4.4 pounds of fat weight and added 2.3 pounds of lean weight. The 61-to-80-year-olds lost 4.1 pounds of fat weight and added 2.4 pounds of lean weight, for a 6.5 pound change in their body composition (see Table 1).

These findings indicate that senior men and women improve their body weight and body composition about as much as younger adults in response to a basic program of strength and endurance exercise. It is interesting to note that the seniors developed lean muscle at the same rate as the other participants. Replacing muscle is essential for seniors because sedentary individuals lose over 5 pounds of lean tissue during every decade of adult life. By adding 2.4 pounds of muscle, the seniors in this study reversed almost five years of the aging process after just two months of strength training.

Blood Pressure Changes

All three groups began the basic fitness program with similar diastolic blood pressure readings (76.1 mm Hg to 80.1 mm Hg). However, the average systolic blood pressure for the 61-to-80-year-olds was considerably higher (143.1 mm Hg) than for the 41-to-60-year-olds (127.9 mm Hg) and the 21-to-40-year-olds (121.2 mm Hg).

As presented in Table 2, all three age groups lowered their resting blood pressure as a result of the eight-week exercise program. The seniors, however, experienced the greatest improvement, with a 3.7 mm Hg decrease in diastolic blood pressure and a 6.2 mm Hg reduction in systolic blood pressure.

The change in systolic blood pressure was particularly important to the senior participants because they began the study above the hypertensive level (140 mm Hg), but ended within the normal range.

Discussion of Findings

The results of this relatively large research study should be encouraging news for senior men and women. Consider the following key findings for the 341 older adults who completed the eight-weight basic fitness program.

1. Seniors can safely participate in a well-designed and carefully supervised program of strength exercise. Of course, all participants should have their physician's approval before beginning an exercise program.

2. Seniors can improve their body composition. The seniors in this exercise program reduced their percent fat by 2.0 percent after just two months of training.

3. Seniors can decrease their fat weight. The senior subjects lost more than 4 pounds of fat weight during the eight-week training period.

4. Seniors can increase their lean weight. The seniors in this study added 2.4 pounds of lean weight after two months of training.

5. Seniors can reduce their resting blood pressure. Following eight weeks of regular exercise, the senior subjects experienced a 3.7 mm Hg drop in their diastolic blood pressure and a 6.2 mm Hg drop in their systolic blood pressure.

6. Seniors can develop physically active lifestyles, even after years of sedentary behavior. Over 90 percent of the senior program participants continued to exercise after the completion of the study.

In summary, seniors have much to gain from regular strength training, particularly as part of a supervised exercise program. The senior men and women in this study reported looking, feeling, and functioning better, which is consistent with their recorded improvements in body weight, body composition, and resting blood pressure. It appears that an hour of exercise two or three times a week is one of the best investments seniors can make for their health and fitness.

Table 1

Changes in body weight and body composition for young, middle-aged and older program participants (N=1132).

*Statistically significant change (p<.01).

Table 2

Changes in resting blood pressure for the young, middle-aged, and older program participants (N=785).