Holding Your Breath During Sit-Ups Could Be Hard on Your Blood Pressure
People with low back problems often do sit-ups as part of their exercise programs. Stronger abdominal muscles give more support to the lower back. Doctors and therapists know how sit-ups affect the muscles and the spine. But they don't always know how sit-ups affect blood pressure. This could be important for low back patients who are out of shape or who have heart problems.
These researchers studied the way partial sit-ups (also called crunches) affected blood pressure and heart rate in 14 healthy people under 40 years of age. Blood pressure was measured before, during, and after doing crunches. The subjects did regular crunches and oblique crunches, which involve twisting to each side to work the oblique abdominal muscles. The subjects also used a common type of home exercise machine that works the abdominals. People with back pain are more likely to use machines to do sit-ups because the machines are thought to take some of pressure off the neck.
Subjects did five of each type of crunch. All crunches were done with the arms folded over the chest and were held for three seconds. The researchers made sure the crunches were done with correct breathing--exhaling while sitting up, and inhaling while relaxing down. Heart rate and blood pressure went up for all three types of sit-ups, but especially for the oblique crunches. All subjects returned to their resting blood pressure and heart rate within two minutes. They all reported that the sit-ups were easy to do.
The subjects were also tested doing crunches while they held their breath. Breath holding while doing sit-ups is a common mistake made by exercisers. In these tests, blood pressure went up twice as much as while breathing correctly, although heart rates were about the same.
Because this study was done with young, healthy subjects, there was probably much less increase in heart rate and blood pressure than would be seen among out-of-shape patients or patients with heart problems. The authors recommend that patients who do sit-ups should be monitored to be sure they are breathing correctly. They also suggest that doctors and therapists should be careful about assigning sit-ups (especially oblique sit-ups) to patients with heart problems or high blood pressure. Future research could help define how sit-ups affect the blood pressure and heart rates of patients who are not as fit as the subjects in this study.
Jonathan T. Finnoff, DO, et al. Acute Hemodynamic Effects of Abdominal Exercise With and Without Breath Holding. In Archives of Physical Medicine and Rehabilitation. July 2003. Vol. 84. No. 7. Pp. 1017-1022.