Endurance Training OK in Chronic Illness—With Clinician Input

Question: How do you counsel an obese 50-year-old male patient with type 2 diabetes, who has high blood pressure and high cholesterol, when his 22-year-old son has challenged him to train for a triathlon?

Answer: Say a review of this patient's medical records reveals that he has type 2 diabetes, diagnosed 5 years ago. The patient is on metformin, and his last glycated hemoglobin (A1C) indicated an average blood glucose of 190 mg/dl. He has hypertension of several years' duration, for which he is on a combination beta-blocker/diuretic. His blood pressure readings are generally 150/95 mmHg. The patient takes a statin for hypercholesterolemia, and his last LDL cholesterol reading was 90 mg/dl. Other measurements are height 5 ft 9 in, weight 93 kg (205 lb), body mass index (BMI) 32, and waist circumference 106.7 cm (42 in).

CONDITIONS TO CONSIDER

If a patient has had diabetes >25 years or has other cardiovascular risks, an exercise stress test is called for before implementing an activity program. An exercise stress test would also be useful to evaluate our patient's blood pressure response. An exaggerated systolic response (>210 mmHg) would warrant modifying his exercise intensity, especially in the implementation phase. Although stage 1 hypertension is not a contraindication for exercise, stage 3 hypertension (systolic >180 mmHg and/or diastolic >110 mmHg) should be controlled medically before the start of an activity program.

Beta-blockers interfere with heart-rate response to exercise, which can create issues for those trying to achieve a training heart rate,¹ and may mask symptoms of hypoglycemia. Diuretics can cause electrolyte disturbances.¹ While many patients exercise successfully on beta-blockers and/or diuretics, our patient is not adequately controlled on his current regimen, so treatment with another agent, such as an angiotensinconverting enzyme (ACE) inhibitor, angiotensin-receptor blocker (ARB), or calcium antagonist, would be recommended.

Hypertensive patients should be instructed to avoid isometric resistance exercises associated with Valsalva maneuvers to avoid spikes in systolic blood pressure.¹

Although exercise generally lowers blood glucose, those with fasting levels ≥250 mg/dl can have a paradoxical rise with exercise. For them, better control is recommended before starting an activity regimen. Conversely, those with a history of low blood glucose (<80 mg/dl) need to correct this pharmacologically before beginning a program.

For patients on oral hypoglycemic agents, careful monitoring of blood glucose during the implementation phase of the activity program ensures that dosing can be adjusted appropriately. Patients on insulin may need to reduce their dose to avoid hypoglycemia. Exercise performed within 1–2 hours of insulin injection can speed its absorption and time to peak effect. Altering the time of either the injection or the exercise can help moderate this.²

FREQUENCY, INTENSITY, TIME

A regimen emphasizing endurance training (jogging, cycling, swimming, etc.) is appropriate for a middle-aged patient with diabetes. Providers should emphasize frequency of exercise sessions; 5–6 times/week is preferable to develop a consistent glucose response. The length of time per session should build gradually, with an eventual target of 30–60 minutes.

Once the patient achieves optimal frequency and time per session, the goal should be moderately intense sessions. The patient should be perspiring and short of breath, but still able to talk while exercising.

Implementing an exercise program is a critical part of the ongoing treatment plan for adults with chronic health conditions, including diabetes.³ Long-term benefits include reductions in weight and cardiovascular risk, increased insulin sensitivity, and improved blood glucose regulation, particularly in type 2 patients. A physician's input can be an important motivational tool. ▪