Heart Disease and Exercise

Physical exercise is a potent primary and secondary preventer of cardiovascular illness, particularly that due to ischaemic heart disease. Evidence continues to accumulate that taking up exercise to prevent cardiovascular disease, or to reduce its risk of recurrence in those already affected by it, is efficacious and not associated with any appreciable harmful effects, if performed with appropriate safeguards.

Regular physical exercise is thought to mediate its beneficial effects through:¹

• Reducing the incidence and severity of obesity and the consequent risk of type 2 diabetes (obesity being more important than inactivity in the risk of developing type 2 diabetes).²
• Improved glucose tolerance.
• Enhanced fibrinolysis.
• Improved endothelial function.^3,4
• Decreased sympathetic tone and enhanced parasympathetic tone.
• Lowering of blood pressure.
• Improved lipid metabolism.
• Other factors, as yet unelucidated.

It is thought that physical inactivity roughly doubles the risk of coronary heart disease and is a major risk factor for stroke.⁵ The US Nurses' Health Study demonstrated that there is a significant beneficial effect from regular exercise that is 'dose-dependent' in terms of prevention of both diabetes and coronary heart disease.⁶ Relative risk reduction can be significant, with those in one study from the most active quintile having a relative risk of cardiovascular disease of 0.46 compared to those in the least active quintile.⁷ Regular walking at a brisk pace and spending fewer hours per day sitting may be as effective in reducing risk as more vigorous exercise,⁸ but the main message is that exercise works in prevention of coronary heart disease.
As well as the direct physical benefits on the body's cardiovascular and metabolic parameters, exercise also provides benefits through reduction of the effects of stress, amelioration and prevention of depressive illness/anxiety in those who are at risk of, or suffering from, cardiovascular disease, and improved self-esteem. Interestingly the beneficial effects of alcohol on reducing heart disease are not measurable in those who exercise as they are in 'couch potatoes'.⁹

There is no clear consensus on the basis of trial data as to the optimal duration, frequency and type of exercise in primary or secondary prevention of coronary artery disease. However, it can be agreed that exercise undertaken to prevent coronary artery disease, in order to be effective, should be:

• Sustained in the long-term
• Regular, i.e at least 4–5 days per week
• Last for about 30 minutes
• Be of mild to moderate intensity, i.e. enough to make people feel warm and out of breath, but not so vigorous as to cause extreme breathlessness.

• Useful activities would include regular walking, cycling, swimming, gardening or dancing.
• Aerobic exercise is thought to be more beneficial and less risky than anaerobic exercise.
• Patients should be advised to avoid exertion that causes straining or raised intra-abdominal/intra-thoracic pressure such as weightlifting etc. if they are inactive and/or are suffering from coronary artery disease.
• Sedentary people should start with mild exertion for short periods, and then gradually build the duration and intensity of the exercise over a few weeks.
• It is best to avoid sudden, erratic bouts of exercise in middle-age or in those suffering from coronary artery disease as there is good evidence that it increases the risk of myocardial infarction and sudden cardiac death in these groups.¹⁰
• There is no evidence that vigorous, prolonged exertion provides any further benefit than moderate, gentle, aerobic exercise of moderate duration, but more extreme exercise does appear to increase the risk of adverse cardiac events.¹⁰
• Those that take regular exercise are much less likely to develop complications as a consequence of vigorous exercise.¹¹
• There is some evidence to suggest that the risk of adverse events due to exercise is increased in those who exercise early in the morning.¹²
• There is evidence that the benefits of regular exercise are available to all, including healthy older patients, particularly in terms of peripheral blood flow mediated through enhanced endothelial nitric acid production.¹³

• Any patients who have suffered myocardial infarction or episodes of angina should be encouraged to incorporate exercise into their lifestyle in order to reduce their risk of further cardiac events.
• A history of MI or angina is not a contraindication to an ongoing exercise programme.
• Patients should take care to build exercise gradually if coming from a sedentary baseline, and exercise within the limits of any angina, breathlessness or claudication.⁵
• It is best to avoid outdoor exercise in very cold weather, in strong winds or exercising when experiencing chest pain.⁵
• Any patient who has had an MI should undergo initial assessment in a dedicated cardiac rehabilitation service; they will be given an exercise programme based upon their symptomatology and their exercise performance on a treadmill whilst having their heart rate response measured.
• It is essential that patients 'warm-up' and 'warm-down' before and after exercising, as a failure to do so can further increase the risk of cardiac events at the beginning of, and after, exercise.
• 'Warm-up' and 'warm-down' routines are taught as part of a cardiac rehabilitation programme.
• There is good evidence from many nations of the benefits of exercise prompted and sustained through cardiac rehabilitation programmes and patients should be strongly encouraged to enrol and participate in them.¹⁴
• The NSF target for participation in cardiac rehabilitation after MI/coronary revascularisation is 85%, but very few trusts attain this target and participation seems to be falling.¹⁵

General considerations

• It is common for the cohort of people (men and women alike) who suffer from coronary artery disease to experience sexual difficulties, particularly after a major event such as an infarct or revascularisation procedure.
• This may be due to occult organic vascular disease, psychological factors, new medication or any combination of these.
• There appears to be a commonly believed myth that sexual activity is more dangerous than other equally strenuous forms of exertion, but there is no convincing evidence that this is the case.¹⁶
• Sexual activity is not particularly demanding on the heart and analysis has shown myocardial oxygen requirements to be similar to climbing two flights of stairs or ordinary occupational tasks, when carried out with a familiar and caring partner.¹⁷
• It is good practice to specifically discuss sexual matters with patients who have had coronary events, to reduce anxiety about their raising the issue, address any problems and help overcome difficulties if possible; this is particularly so for men suffering erectile dysfunction.¹⁷

Specific factors to take into account

• Tailor individual advice to previous levels of activity, future intentions and cardiovascular reserve/symptoms.¹⁷
• Reassurance that an MI or coronary artery revascularisation does not mean the end of an active sexual life is an important part of the cardiac rehabilitation process; this should be borne in mind for single people as well as those in a stable relationship.
• Anxiety and inhibitions associated with sexual abstinence/inactivity may be more harmful in terms of cardiovascular risk than continuing with an active sex life.¹⁸
• Sexual activity can start once modest levels of exercise become part of the patient's normal lifestyle and this may be within days following the event if there are no significant immediate complications or significant symptoms.¹⁷
• Masturbation can be used as a means to reassure the patient that they are physically capable of sexual activity, that their sexual organs are functioning as before, and that orgasm can still be attained.
• It is a good idea to avoid sexual activity following a large meal or alcohol intake, especially initially after a cardiac event.¹⁸
• Initial sexual encounters after a coronary event should ideally be in a familiar setting with a trusted, regular sexual partner, start gently and progress slowly.
• Sexual partners should be encouraged to adjust their sexual positions and means of sexual gratification to suit their phase of recovery from their illness.
• Penetrative sex is not the only means of sexual gratification; adequate foreplay (a 'warm-up') and other sexual techniques may need to be explored if there is a physical limitation on one partner's activity due to myocardial symptoms.
• Patients who have had femoral puncture as part of coronary angiography and angioplasty/stent insertion may be locally tender and have to adapt their sexual practices until the area is healed; bruising patterns may change after sexual activity and patients should be aware that this may occur.

Some notes on the treatment of impotence in men with coronary artery disease¹⁷

• Erectile dysfunction is relatively common in men with cardiovascular risk factors.
• It can be worsened by medication (particularly beta-blockers) but stopping treatments is unlikely to resolve the problem unless there is a definite temporal relationship to starting a new therapy.
• Although most cases will be due to organic microvascular disease, don't forget the relevance of psychological factors after cardiac events; is depression or anxiety a possible contributory factor?
• The full range of therapies for erectile dysfunction should be considered, including the use of sildenafil (Viagra®).
• Take care if using intra-cavernosal injections/vacuum pump therapy in patients on anticoagulants (and anticipate that there may be more bruising following commencement of aspirin).
• Sildenafil is contraindicated in patients taking nitrates and/or nicorandil due to the risk of profound hypotension and cardiovascular collapse; consider alternative anti-anginal therapies.
• PRN nitrates should not be used in patients taking sildenafil who experience angina during intercourse; a 24-hour gap should be left between use of sildenafil and use of PRN nitrates.

Conclusion

• Sexual intercourse is not contraindicated in patients with coronary artery disease and should be considered no more dangerous than other similar exertions, despite its popular depiction in various media as a potentially lethal activity for those with heart trouble.
• Sexual dysfunction is relatively common among those with heart disease and it should be considered as part of the patient's cardiac rehabilitation and discussed openly if the patient is willing to do so.
• Erectile dysfunction can be treated with a variety of means in men with coronary artery disease, including the use of sildenafil, provided appropriate notice is taken of other medications (particularly nitrates and nicorandil).