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Background. The purpose of this study was to examine the relationships among relative maximal heart rate (%HRmax), maximal heart rate reserve (%HRmax reserve), and maximal oxygen uptake (%V[O.sub.2]max) during submaximal exercise by elderly subjects. Methods. V[O.sub.2]max and HRmax were determined on 36 women and 19 men, 60 to 80 yrs of age, by a maximal treadmill test to volitional exhaustion. On a separate day, subjects underwent a submaximal treadmill protocol consisting of three 6-min exercise stages at treadmill speeds and grades estimated to elicit 40%, 60%, and 80% of HRmax reserve. Cardiorespiratory responses were determined during mins 4-5 and 5-6 of each stage. Results. Measured exercise intensities expressed by the three methods were: %HRmax reserve = 36, 55, and 79%; %HRmax = 65, 75, and 88%; % V[O.sub.2]max = 53, 69, and 88%. %HRmax was greater (p < .05) than % V[O.sub.2]max at 53 and 69% of V[O.sub.2]max. %HRmax reserve was less (p < .05) than % V[O.sub.2]max for all three intensities. Slopes and intercepts for the linear regression equations relating % V[O.sub.2]max with %HRmax and with %HRmax reserve differed between men and women (p < .05). The regression equation relating % V[O.sub.2]max and %HRmax was y = -22.8 + 1.2 (%HRmax) -13.0 (Gender) + 0.2 (%HRmax x Gender): standard error of the estimate (SEE) = 9.7% and [R.sup.2] = .71. The regression equation relating % V[O.sub.2]max and %HRmax reserve was y = 32.4 + 0.7 (%HRmax reserve) -10.9 (Gender) + 0.2 (%HRmax reserve x Gender): SEE = 9.8% and [R.sup.2] = .70 (Gender: F = 0; M = 1). Conclusions. The data indicate that there is considerable variability among methods of expressing exercise intensity and that %HRmax more closely represents % V[O.sub.2]max than does %HRmax reserve (p < .05) in older adults. These results are in contrast to what has been shown with younger subjects and with American College of Sports Medicine guidelines for exercise prescription.

Background. Hormonal responses of elderly individuals experiencing pre-syncopal symptoms during head-up tilt testing (HUT) were compared with responses of nonsymptomatic subjects both before (T1 and after (T2) 6 months of endurance training. Methods. Based on responses to HUT at T1, 35 men and women (ages 61-79 years) were placed into symptomatic and nonsymptomatic groups for analysis. Symptomatic subjects (n = 5) experienced lightheadedness, nausea, sweating, or syncope during T1 HUT but completed 15 minutes of HUT at T2. Training consisted of treadmill walking or stairclimbing 3 x /wk, 30-45 min/day, at 75-85% of maximal heart rate reserve. Adrenocorticotropic hormone (ACTH), vasopressin, aldosterone, norepinephrine, epinephrine, hemoglobin, and hematocrit were measured during supine rest prior to HUT, and either at the end of the 15-minute HUT or at symptom onset. Plasma volume (PV) was measured at supine rest; tilt-induced changes in PV were calculated from changes in hemoglobin and hematocrit. Result During T1 HUT, symptomatic subjects had greater increases in vasopressin and a greater rate of PV loss (p < .05). Increases in ACTH and aldosterone were greater in symptomatic subjects at T1 and T2, while increases in norepinephrine were greater at T2 (p < .05). Reductions in tilt-induced vasopressin concentration and a decreased rate of PV loss were seen at T2 in symptomatic subjects. Conclusions. T1 results from symptomatic subjects are consistent with greater stimulation of volume-sensitive receptors induced by a greater rate of fall in PV. Exercise training resulted in increased tilt tolerance for symptomatic subjects associated with reductions in vasopressin concentration and rate of PV loss during tilt.

One of the obvious consequences of aging is that we slow down; our ability to process and react to specific external information (psychomotor performance) has been said to diminish. However, there have been recent suggestions that physical activity may reduce the effect of age on psychomotor performance and that exercise training can improve it. While that may be true for older persons who have been physically active for most of their lives, it was found that for sedentary people, a six-month training program did not do much to improve either reaction time (RT) or speed of movement (SM), although aerobic capacity did increase. In this study, the effect of a six-month aerobic and variable resistance exercise training on reaction time (RT) and speed of movement (SM) was measured in 49 healthy but sedentary men and women who ranged in age from 70 to 79. The subjects were divided into three groups, including a control group, a walk/jog group and a variable resistance strength training group. Those in the control group were asked not to change their life styles over the six months of the study; those in the other two groups underwent progressive training programs. There were no differences with respect to total reaction time, motor time, or speed of movement between the groups. The authors suggest that to elicit significant improvements in psychomotor performance, less fit subjects, younger subjects, more complex reaction time tasks, and training for longer periods may be required. (Consumer Summary produced by Reliance Medical Information, Inc.)

Examines the current guidelines on exercise for physical fitness and identifies the issues that influence the updating of the American College of Sports Medicine (ACSM) exercise statement. Health benefits of low intensity/volume physical activities; Difference between exercise prescription for fitness and physical activity for health; Recommendations on training progression; Permanent lifestyle change.

A new instrument for testing the strength of lumbar extensor muscles has been developed. A group of 15 healthy individuals underwent a 10-week training period designed to improve the strength of the lumbar, lower back, musculature. The subjects' muscular lumbar strength was measured both before the training period and at its conclusion. The tests allowed strength measurements to be made through a complete range of motion. Training of the lumbar musculature was found to be significantly increased by exercising only one day per week for 10 weeks. The increase in muscular strength was remarkable, ranging from a low of 42 percent to a high of 102 percent. These results probably indicate the low level of muscular conditioning of these lower back muscles and that even modest training can make significant improvements in the range of motion and strength of these muscle groups. The data may have important implications for individuals who suffer from difficulties of the lower back, and who may gain significant improvement from such training programs.