Endurance exercise like swimming can help lower the risks for cardiovascular diseases. However, a moderate exercise prescription on land can sometimes be recommended over swimming for patients with cardiovascular disease (CVD).

Inactivity, smoking, lipids (cholesterol), high blood pressure, stress, weight, and diabetes are modifiable, meaning we can change our lifestyle—embrace a correct daily diet and exercise regime—and have a positive impact.

EXERCISE PREVENTION
Any type of low-medium intensity endurance exercise like walking, cycling, jogging, aerobic classes, or swimming for 30-60 minutes per day, most days of the week, can help to prevent the risk of CVD.  Why?

Endurance exercise at low-moderate intensity reduces blood pressure, stress, risk of weight gain, and the consequences of obesity. In addition, this type of exercise increases your HDL and the TC/HDL ratio, which reduces the risk of thrombus formation that increases insulin sensitivity, reducing the risk of diabetes.

Swimming and water sports are endurance exercises. Swimming lowers some of these physiological risk factors. 

SWIMMING AND OBESITY
Dietary restriction combined with endurance exercise training represents an effective strategy to promote weight loss and reduce fat mass in obese patients. Exercise programs without dietary restriction are less efficient. Addition of exercise to a dietary restriction program does not induce a greater fat mass loss than dietary restriction alone. However, the inclusion of an exercise training program is important to prevent a decrease in lean body mass. It also increases relative visceral fat mass loss and improves dietary compliance. Most importantly, it helps maintain long-term weight control. The amount of training is a more important predictor of fat mass loss than training intensity.

Eduard Gappmaier, PhD, PT,  at the University of Utah, studied 38 middle-aged obese women (25-47 percent body fat) who participated in a 13-week exercise-diet program: 40 min/session, four times a week at 70 percent of age-predicted maximum heart rate swimming or walking. All three experimental groups (walking on land, swimming, and walking in the pool) reported the same significant reductions in body weight, in percent of body fat (-3.7 percent), in skinfold and girth measurements.

This is an important result because swimming for overweight people can be a valid alternative to weight-bearing aerobic exercise on land as long as similar intensity, duration, and frequency are used. In fact, in water, submaximal heart rate and RPE (rating of perceived exertion) are reduced, probably due to the lessening of weight bearing. Consequently, the exercise feels more enjoyable with less impact and fatigue. The chances that subjects will continue to exercise increases with positive impact on their health.

SWIMMING AND CHOLESTEROL
Sandrija Sideraviciute at the Lithuanian Academy of Physical Education in Lithuania reported that a long-term (14 weeks) swimming program (45 min/session, twice per week) increased aerobic capacity, decreased body fat mass in diabetic and healthy young girls, but increased HDL (the good cholesterol) only in the healthy girls. This study indicates that swimming can help to prevent high cholesterol by increasing HDL. However, if subjects are already diabetic, swimming may not help to improve their lipid profile. Long-term swimming programs also improved aerobic capacity, reduced body fat mass in all participants, and reduced high-density lipoprotein levels only in healthy subjects.

SWIMMING AND DIABETES
The same laboratory reported that the same long-term swimming program improved glycemia for both healthy and diabetic young girls, with greater improvement for the diabetic subjects. This is another important result indicating that swimming can help to control blood glucose in diabetic subjects.

SWIMMING AND BLOOD PRESSURE (BP)
Exercise is a positive and effective addition to other lifestyle measures in the prevention of hypertension. Adherence to either supervised or unsupervised moderate-intensity exercise is sufficient to reduce BP in the short and long term.

However, in older women, some scientific evidence showed that regular swimming increased BP.

SWIMMING AND CHRONIC HEART FAILURE (CHF) PATIENTS
Endurance exercise also has benefits for patients with cardiac dysfunctions. Some of these benefits include: reduction of submaximal heart rate, anti-atherosclerotic effect (reduction of BP, improving of blood lipids, increased insulin sensitivity), decrease of blood viscosity, decrease of platelet adhesiveness, and reduction of anxiety and stress.

Some research showed that CHF subjects may have good tolerability for low-speed swimming in warm water due to some beneficial hemodynamic effects (decreased heart rate and increased ability of the heart to be filled with blood during relaxation). On the contrary, there is some evidence that immersion in the water resulted in abnormal mean pulmonary artery pressure (PAm) and mean pulmonary capillary pressures (PCPm). Therefore, swimming for CHF patients should not be taken without medical consulting.

Luisa Sullivan
is a Colorado-based cyclist and cycling coach.

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