Many gyms now advocate inversion devices for increasing flexibility, helping reduce blood pressure, improving circulation, reducing stress and relieving back pain. Some companies also advocate the performance of muscle-strengthening exercises during inversion.
A recent study sheds light on this topic. Fifty young male subjects, ages 18 to 31 years, who ranged in weight from 118 to 222 pounds and in bodyfat levels from 6.4% to 27.7%, were studied for their blood pressure and heart rate responses. Each subject was fitted with inversion boots and then told to stand for five minutes during which physiological measurements were made. Subsequently subjects were positioned on the inversion device and rotated slowly (about 15 seconds) to an upside-down position. They remained in this position for three minutes before being returned to the standing position. Blood pressure and heart rate were measured during inversion and immediately after.
The results were quite surprising. While there was a decrease in heart rate from 100 beats per minute prior to inversion to about 80 beats per minute during the three minutes of inversion, immediately upon returning to the upright position, pulse increased to 110 beats per minute and then decreased to about 93 beats per minute.
For blood pressure, the results were more dramatic. Prior to inversion, the pulse was about 127 systolic and 87 diastolic, which is quite normal. Immediately upon inversion, the systolic pressure increased to 153 and diastolic pressure to slightly over 100. Throughout inversion, systolic blood pressure remained at 150 and diastolic remained slightly above 100. Following inversion, there was a decrease in systolic pressure to 125 and diastolic pressure to about 85.
The authors of the study point out that people who use inversion devices should be very careful. Test subjects were normal young adults with normal blood pressure, whose blood pressures increased significantly after inversion. The authors went on to state that many people are being inverted in fitness facilities with little knowledge of the possible consequences. Such practices may be dangerous for hypertensive or borderline-hypertensive persons. If a person performs exercise while in the inverted position, it is likely that there will be a further increase in blood pressure; this could be very dangerous for those people predisposed to heart disease or with existing high blood pressure. The authors conclude that people should not exercise in the head-down position until further research, is completed. No attempt was made to document the effects on flexibility or reduction of stress.
The Old Boys Brigade advice would be to proceed with caution. If you have an existing medical problem, it would be wise to check with your physician before engaging in such activities.