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Expert London Cardiologist for your Heart Health
Cardiovascular Health
Physical activity is one of the most powerful and underused medicines in cardiology. Dr Nijjer explains how the right exercise — in the right dose — can transform blood pressure, cholesterol, and long-term cardiac outcomes.
The Medicine You Can Prescribe Yourself
If exercise could be bottled as a pill, it would be the most prescribed medication in cardiology. Large-scale evidence — from decades of cohort studies and randomised trials — confirms that regular physical activity reduces the risk of heart attack, stroke, and cardiovascular death by 20–35%. No single drug achieves that across a healthy population.
Exercise works through multiple, overlapping mechanisms. It lowers blood pressure, improves the cholesterol profile, reduces insulin resistance, decreases systemic inflammation, strengthens the heart muscle itself, and improves the function of the arteries' inner lining — the endothelium. These benefits compound over years, and even modest improvements to fitness carry meaningful reductions in cardiac risk.
The World Health Organisation recommends at least 150 minutes of moderate-intensity aerobic activity per week for adults — equivalent to 30 minutes on five days. Yet only around 30% of UK adults meet this target. For patients with established heart disease, guided exercise is not only safe but actively recommended by the European Society of Cardiology in every major set of clinical guidelines.
An important distinction: Patients with established cardiac conditions should not simply start a new exercise programme without guidance. The right type, intensity, and progression depends on your specific diagnosis, current medications, and how well your condition is controlled. Dr Nijjer can advise on a tailored exercise plan and refer for formal cardiac rehabilitation where appropriate.
The Evidence in Numbers
Prescribing Exercise as Medicine
Cardiologists prescribe exercise using the F.I.T.T. framework — Frequency, Intensity, Time, and Type. The targets below reflect current ESC and WHO guidelines for adults with or without established cardiovascular disease.
5 days per week
Aim for activity on most days of the week. Three to five sessions of structured exercise is the minimum for cardiovascular benefit. Daily light movement (walking, stairs) adds further benefit beyond formal exercise sessions.
Moderate — you can talk but not sing
Target 50–70% of your maximum heart rate for moderate intensity. A simple test: you should be able to hold a conversation but find it too hard to sing. Vigorous intensity (running, cycling fast) delivers additional benefit but requires medical clearance in heart disease patients.
150 min/week moderate
or 75 min/week vigorous
The WHO and ESC both recommend 150–300 minutes of moderate aerobic activity per week, or 75–150 minutes of vigorous activity. These targets can be accumulated in bouts as short as 10 minutes — you do not need one long session.
Aerobic + Resistance
Aerobic exercise (walking, cycling, swimming, jogging) provides the strongest cardiovascular benefit. Resistance training (weights, resistance bands) improves metabolic health and is recommended two to three times per week as a complement, not a replacement.
Evidence-Based Benefits
Exercise acts on both blood pressure and cholesterol through distinct physiological mechanisms. Understanding how it works helps explain why consistency matters more than intensity, and why even modest increases in activity carry clinical benefit.
Regular aerobic exercise reduces resting blood pressure by improving arterial compliance — the arteries become more elastic and less resistant to blood flow. Exercise also reduces sympathetic nervous system activity (the "stress response"), lowers circulating adrenaline levels at rest, and promotes the release of nitric oxide from the arterial lining, causing sustained vasodilation.
A landmark meta-analysis of 93 randomised trials (Cornelissen & Smart, 2013) found that aerobic exercise reduced systolic blood pressure by an average of 8.3 mmHg in hypertensive individuals — comparable to a single antihypertensive drug. The blood pressure-lowering effect is additive to medication.
Exercise influences cholesterol in two important ways. First, it raises HDL cholesterol — the "good" cholesterol — by increasing the production of apolipoprotein A-I, the main protein component of HDL particles. Second, it reduces triglycerides by enhancing lipoprotein lipase activity, which clears triglyceride-rich particles from the bloodstream after meals.
The effect on LDL is more modest but still meaningful — a combination of aerobic and resistance training can achieve a 10–20% reduction in LDL when sustained over months. For patients with borderline LDL, exercise may delay or reduce the need for statin therapy. For those already on statins, exercise provides complementary and additive cardiovascular protection.
Beyond direct effects on blood pressure and cholesterol, exercise improves cardiovascular health by reducing visceral fat (the dangerous fat around the internal organs), lowering markers of systemic inflammation such as CRP and IL-6, and improving insulin sensitivity — which is directly linked to arterial stiffness and atherosclerosis risk.
Even without significant weight loss, regular exercise independently reduces cardiovascular risk. "Fit and overweight" individuals have substantially lower cardiac mortality than "unfit and normal weight" individuals, a finding replicated across multiple large cohort studies. Fitness is a more powerful predictor of cardiovascular outcome than BMI alone.
Exercising with Heart Conditions
Angina is chest discomfort caused by reduced blood flow to the heart muscle during exertion. Many patients avoid all physical activity after a diagnosis of angina — but this is not the right approach. Supervised, appropriately paced exercise is one of the most effective treatments for stable angina.
Regular moderate exercise in patients with stable angina gradually increases what is known as the "ischaemic threshold" — the level of exertion at which symptoms appear. Studies show that a structured exercise programme can raise this threshold by 30–40% over three months, allowing patients to do significantly more before symptoms develop.
The mechanism involves the development of collateral circulation (small new vessels that bypass blocked segments), improved endothelial function in the coronary arteries, and reductions in the heart's oxygen demand at any given workload. Exercise also reduces anxiety about activity — a common and limiting response to angina symptoms.
Exercise-based cardiac rehabilitation — usually delivered as a supervised, group-based programme over eight to twelve weeks — has been shown to reduce angina symptoms, improve quality of life, and reduce the rate of future coronary events in patients with stable coronary artery disease. It is strongly recommended by NICE guidelines.
Seek urgent medical attention if: your chest pain occurs at rest, occurs more frequently or with less exertion than usual, lasts more than 15 minutes, or is accompanied by breathlessness, sweating, or nausea. These are potential features of unstable angina or a heart attack and require immediate assessment.
Recommended
Use Caution / Avoid
For many years, heart failure patients were advised to rest and avoid exertion. Modern evidence has completely reversed this guidance. Exercise training in heart failure is now one of the most robust and well-evidenced interventions to improve quality of life, reduce hospital admissions, and — in some studies — reduce mortality.
Heart failure causes exercise intolerance through reduced cardiac output, muscle wasting, and deconditioning — a vicious cycle that gets progressively worse with inactivity. Regular, graded exercise training interrupts this cycle by improving skeletal muscle efficiency, improving the heart's ability to fill and pump, and reducing the neuro-hormonal overdrive (excessive adrenaline and aldosterone) that characterises the disease.
The HF-ACTION trial — the largest randomised controlled trial of exercise in heart failure — demonstrated that a structured aerobic exercise programme reduced hospitalisation by 15% and improved exercise capacity by a clinically meaningful amount. The ExTraMATCH meta-analysis confirmed a 35% reduction in all-cause mortality with regular exercise training.
Exercise must be carefully graduated and supervised, particularly in the early stages or after a period of decompensation. A formal heart failure rehabilitation programme — where available — provides individualised exercise prescription with continuous monitoring. Many patients begin on a static cycle ergometer with heart rate and oxygen saturation monitoring before progressing to other activities.
Read the full Heart Failure guideAppropriate Exercise
Use Caution / Discuss First
Stop exercising and seek advice if: breathlessness at rest worsens, you develop ankle swelling, you feel dizzy or light-headed during exercise, or you notice palpitations or chest pain during activity.
Exercise guidance in valvular heart disease depends critically on the type of valve affected, the severity of the problem, and whether it has been treated. Broadly speaking, mild-to-moderate valve disease does not preclude regular moderate exercise — but severe or symptomatic valve disease requires specialist assessment before any exercise programme begins.
Aortic stenosis (AS) — the narrowing of the aortic valve — is the most common severe valvular condition in adults over 65. In severe aortic stenosis, vigorous exercise carries a risk of collapse or arrhythmia because the heart cannot increase its output on demand. Symptomatic severe AS requires valve replacement (TAVI or surgical) before vigorous exercise is resumed. Mild-to-moderate AS typically permits moderate aerobic exercise with annual monitoring.
Mitral regurgitation (MR) — leaking of the mitral valve — is generally better tolerated during exercise than AS. Patients with mild-to-moderate MR who remain asymptomatic can usually undertake moderate exercise without restriction. Severe MR with breathlessness warrants cardiology review and often surgical or percutaneous repair before intensive exercise.
After valve repair or replacement, cardiac rehabilitation is strongly recommended. Most patients can return to regular moderate exercise within six to twelve weeks of recovery, with supervised rehabilitation accelerating the process and ensuring safe progression. Running, cycling, and swimming are all appropriate in the longer term for most patients with repaired valves.
Read the full Valve Disease guideGenerally Appropriate (Mild–Moderate)
Seek Review Before Proceeding
Returning to Exercise
Coronary angioplasty (percutaneous coronary intervention, or PCI) with stent placement reopens a blocked coronary artery and relieves angina or treats a heart attack. Most patients are surprised by how quickly they can return to — and benefit from — physical activity after the procedure.
Days 1–7 — Immediate Recovery
Following PCI, most patients are discharged home within 24 hours. The arterial access site (usually the wrist — radial artery) requires 48–72 hours to heal fully. Light walking around the home is encouraged from day one — prolonged rest is counterproductive. Avoid lifting anything heavier than 5 kg from the access-site arm for one week. Driving is usually permitted after 48 hours for elective PCI, or one week after a heart attack.
Weeks 1–4 — Gradual Reintroduction
Begin a structured walking programme: 10–15 minutes daily in week one, building by 5 minutes per week. By the end of week four, most patients can comfortably walk 30–45 minutes at a brisk pace without symptoms. Climbing stairs is usually fine within the first week. Listen to your body — mild fatigue is normal; chest pain, breathlessness, or dizziness should prompt contact with your cardiology team.
Weeks 4–12 — Cardiac Rehabilitation
NICE guidelines recommend that all patients who have had a heart attack or PCI are offered cardiac rehabilitation — a supervised, structured exercise and education programme delivered over six to twelve weeks. Attendance is associated with a 26% reduction in cardiac mortality and significant improvements in fitness, confidence, and quality of life. The programme includes individually graded aerobic exercise, education about medications and risk factors, and psychological support. A referral can be arranged at the time of hospital discharge or through Dr Nijjer's clinic.
3–6 Months — Return to Full Activity
By three to six months after PCI, most patients — particularly those who have completed cardiac rehabilitation — can return to their full range of exercise activities. This includes jogging, cycling, swimming, tennis, and gym workouts. An exercise stress test may be recommended at three months to confirm that the treated artery remains open and to set an objective exercise target. Patients who underwent PCI for a heart attack may take slightly longer than those treated electively for stable angina.
Post-Operative Recovery
Coronary artery bypass grafting (CABG) is open-heart surgery that reroutes blood flow around blocked coronary arteries using grafts taken from the chest, arm, or leg. Recovery takes longer than after angioplasty, but the long-term exercise goals are the same — and cardiac rehabilitation is equally important.
Weeks 1–4: The sternum (breastbone) is divided during surgery and requires six to eight weeks to heal fully. During this period, heavy lifting, pushing, and pulling must be avoided to allow the bone to fuse correctly. Light walking — even within the first week at home — is actively encouraged. Short walks of 5–10 minutes, several times a day, help prevent blood clots, improve lung function, and begin the cardiovascular recovery process.
Weeks 4–8: Walking duration and pace can increase progressively. Most patients can comfortably walk 20–30 minutes by six weeks. Light household activities are resumed during this period. Driving is usually permitted at six weeks if the patient can perform an emergency stop without hesitation and is not taking strong opioid analgesia. An outpatient cardiology review is typically scheduled at six to eight weeks.
Weeks 8–12 and beyond: Cardiac rehabilitation should begin at or around the six-week mark. The programme provides supervised exercise progression, education about secondary prevention, and crucially — the psychological support many CABG patients need. Depression and anxiety are common after cardiac surgery, and exercise is one of the most effective treatments for both. By three to four months, most patients can return to moderate aerobic exercise including swimming, cycling, and jogging. Many patients feel significantly better than they did before surgery as the coronary blood flow is fully restored.
Long-term: The bypass grafts will only remain open if cardiovascular risk factors are well controlled. Exercise, alongside diet, smoking cessation, and medication, is central to protecting the new grafts and preventing future problems. Patients who exercise regularly after CABG have substantially better long-term outcomes than those who remain sedentary.
Appropriate (Weeks 1–8)
Avoid Until Sternum Heals (6–8 Weeks)
Urgent symptoms: Contact your surgical team or call 999 if you experience chest wound pain, opening, or signs of infection; new chest tightness during activity; palpitations; or unexpected breathlessness at rest.
Exercise Safety
Exercise is safe for the vast majority of people with heart conditions when appropriately dosed and gradually progressed. Understanding the warning signs that indicate you should stop and seek advice is essential — and removes the anxiety that often prevents patients from exercising at all.
These symptoms during or immediately after exercise warrant stopping activity and contacting your cardiology team or GP on the same day. If symptoms are severe, call 999 immediately:
After an event: If you collapse, lose consciousness, or experience a cardiac arrest during exercise, call 999 immediately. Do not attempt further exercise until you have had a full cardiology assessment.
The following situations call for a cardiology review before you begin or resume exercise:
For patients who are unsure whether it is safe to exercise, a formal exercise stress test — performed in a clinical setting with ECG monitoring — is often the most reassuring and informative step. This tests the heart's response to graded exercise and identifies any ischaemia or arrhythmia that would otherwise limit activity.
Dr Nijjer discusses exercise and lifestyle as part of every cardiology consultation. For patients who would benefit from formal cardiac rehabilitation or a supervised exercise programme, referrals can be arranged. Appointments are available at Harley Street and across London, often within the same week.