Many patients can take better control of their blood pres-sure with the help of chiropractic care. Exercise can be recommended safely for many who are hypertensive. A recent study determined that physical activity contributes to the control of blood pressure in overweight as well as in lean subjects.1 Yeo, et al., observed a "strong trend" that ten weeks of moderate exercise lowered the diastolic blood pressure among pregnant women at risk of hypertensive disorders.2 Even patients who must take medication for severe hypertension can benefit from mild to moderate intensity exercise.3-4-5 This article offers some advice on how to lessen your risk of malpractice, while providing a valuable service to your patients. High Blood Pressure The pressure in the arteries which is necessary to circulate blood to all areas of the body is normally less than 130 mmHg (systolic) and less than 85 mmHg (diastolic). When resting measurements are consistently above 140 mmHg (systolic) and/ or 90 mmHg (diastolic), the person has hypertension. See Table 1 for a classification system. The prevalence of hypertension increases with age and is more common in males and in sedentary individuals. In 90% of cases, there is no specific cause identified, which leads to the term "essential hypertension." This is usually a complex condition, with hormonal, dietary, vascular, and stress components. The reason for concern is the greatly increased chance of stroke and heart attack, as well as eventual kidney damage when the blood pressure stays high. Effects of Exercise All types of exercise cause a temporary increase in both heart rate and blood pressure, in order to get additional oxygen to the working muscles. When sufficient oxygen is be- ing supplied for the muscles' needs, this is termed aerobic exercise. With more strenuous exercising, an oxygen debt develops, and the exercise becomes anaerobic. One response to anaerobic exercising is an even greater increase in heart rate and also in blood pressure. When exercising is done regularly, the resting blood pressures tend to decrease.6 As the body gets better at supplying oxygenated blood during exercising, the amount of pressure needed to provide blood at rest decreases. This has a beneficial effect on many parts of the body, and may even impact on age-related hearing impairment.7 The challenge is to get sufficient exercise to stimulate this response, without causing a stroke or heart attack during exercising, when the blood pressure is elevated. Avoiding Increased Pressure The simplest approach to avoiding catastrophic increases in blood pressure while exercising is to recommend that the patient perform only aerobic exercises, such as walking, swimming, or bike riding. With those having moderate hypertension (160-179 mmHg/100-109 mmHg) this is the safest way to start. However, in order to maintain (or regain) strength and lean muscle mass, and to establish better spinal support, some form of resistance training is necessary. With guidance in the following four factors, patients with high normal blood pressure and mild hypertension can safely be started on strength-building exercises. Isometric. As a muscle contracts, the adjacent vessels are constricted and blood flow is blocked. Once the muscle relaxes, blood flow returns to normal. If the contraction is maintained, blood pressure is increased in an attempt to push blood through the blockage. Avoiding sustained contractions and encourag- ing full relaxation of muscles being exercised will help prevent excessive pressure increases. This means no isometric exercises, and no "hold" at the point of maximum contraction. This also means consciously relaxing all muscles while exercising, and not carrying any constant muscular tension. Valsalva maneuver. A rapid rise in blood pressure is created whenever we hold our breath and exert. This is called a Valsalva maneuver when it is performed in a clinical setting. To avoid this, patients must be instructed to breathe during exercising. Specific "breathe in/ breathe out" timing is not really necessary; what is important is relaxed breathing to a regular cadence. Final reps. Studies investigating blood pressure during weight-lifting have found that it is during the last repetitions of a set that the pressure becomes greatest, as the muscles tire and have to work harder. The way to avoid this is to use moderate resistance, and avoid exercising to the point of muscle failure (which is sometimes called "maximal effort"). This' will keep the blood pressure from getting too high, yet can still provide a good fitness workout. Rest. A final way to keep the blood pressure moderate during exercising is to enforce frequent rest periods. By planning bouts of exercise interspersed with ■ time to relax and breathe, even hypertensive patients can participate in a strength-building exercise program. The end result will be a healthier body, and often a more normal blood pressure. Effects of Medication Some patients will need medication to control their high blood pressure, especially in the higher-age ranges. While the drugs do decrease the likelihood of strokes and heart attacks, many patients are hesitant to exercise, and they become even more sedentary. There is good evi-. dence that exercise is not contraindicated, and is actually beneficial for patients taking blood pressure medications.3'4 Even exercise which goes beyond the aerobic threshold, if performed correctly and with the precautions listed above, can be safely recommended. However, it is still a good idea to have the patient discuss exercise with the prescribing doctor, and to make sure there are no other contraindications. Clinical Procedures When patients are ready to start on an exercise program as part of their chiropractic care, first check their blood pressure to see into which category they fall. If they are normal, high normal, or have mild hypertension, they should be able to tolerate an exercise plan which includes strengthening. Even when a patient has • to use medication to stay in this range, there is usually no need to limit or modify exercise plans. Avoid isometric or "hold" exercises, always discuss breathing and relaxation, and discourage exercising to muscle failure. With these caveats, there should be little concern about exercise recommendations raising a patient's blood pressure and causing cardiovascular problems. When a patient has a blood pressure reading over 160/100 (if either number is . exceeded), make sure the patient understands the condition and is under the care of a medical doctor for this. Start most such patients on a walking program first for several weeks to monitor their response to aerobic exercise. Once regular aerobic exercise is being successfully accomplished, at least three (but preferably more) times a week, a hypertensive patient is ready to add resistance exercises. Go over the instructions carefully, to make sure that the factors listed above which increase blood pressure are minimized. In general, patients respond to chiropractic care more rapidly when they are exercising regularly, and are doing resistance exercises which improve the support, posture, and coordination of the spine, nra See page 50 for References Kim D. Christensen, DC, C.C.S.P.. D.A.C.R.B., founded the SportsMedicine & Rehab Clinics of Washington. He is a popular speaker, and participates as a team physician and consultant to high school and university athletic programs. He is currently a postgraduate faculty member of numerous chiropractic colleges and is the president of the American Chiropractic Association (ACA) Rehab Council. Dr. Christensen is the author of numerous publications and texts on musculoskeletal rehabilitation and nutrition. He can be reached at Chiropractic Rehabilitation Consulting, 18604 NW 64th Ave., Ridgefield, WA 98642 or by e-mail at kimdchristensen(3)hotmail.com.
