Exercise Exercise

When prescribing exercise, it is important to consider the following:[#american-college-of-sports-medicine.-2013]

  • Ensure atrial fibrillation (AF) patients are compliant with all medications, especially those that help control HR
  • Patients with undiagnosed AF should not exercise until adequately managed by their primary care physician
  • Monitor for irregular and potentially rapid ventricular rates
  • HR at rest should be adequately controlled (<100 bpm)
  • Age-predicted maximal HR targets are not valid
  • HR is unreliable for prescribing exercise intensity
  • A may be intermittent
  • Irregular ventricular responses render assessment of HR inaccurate when using pulse oximetry or HR monitors and may make BP assessment more difficult. For this reason HR should be assessed manually

Exercise is contraindicated under the following circumstances:[#durstine-jl-moore-g-painter-p-et-al.-2009,#hordern-m-dunstan-d-johannes-p-et-al.-2012]

  • Active retinal haemorrhage or recent retinal therapy
  • Current illness or infection
  • Type 1 diabetes, if blood glucose >14 mmol/L and urinary ketones are present
  • Blood glucose < 4mmol/L (hypoglycaemia risk)

If a patient's pre- or post-exercise blood glucose is <5.5 mmol/L, they should consume carbohydrates before exercising.

The exercise clinician should:

  • Monitor blood glucose levels, observing the individual’s blood glucose response to exercise, medications and carbohydrate ingestion
  • Check the patient's skin integrity before every exercise session
  • Ensure that the patient wears appropriate footwear and clothing for exercising
  • Be aware of the signs and symptoms of hypoglycaemia and ensure a carbohydrate source is available at exercise sessions in case it is needed

Beta-blockers may mask symptoms of hypoglycaemia.

 

Individuals with type 2 diabetes may exercise with higher-than-normal blood glucose levels providing they are feeling well and are adequately hydrated. Hyperglycaemia after a meal is likely to reduce during aerobic exercise.[#colberg-sr-sigal-rj-fernhall-b-et-al.-2010]

For patients with concomitant chronic obstructive pulmonary disease (COPD), the following should be considered:

  • Prescribed bronchodilators should be given before exercise training starts. This medication should only be given if spirometry results confirm that such use provides benefits beyond that provided by the long-acting bronchodilators the patient may be prescribed
  • Oxygen saturation should be monitored regularly especially during lower limb exercise training
  • The benefit of supplemental oxygen for those patients who desaturate below an oxygen saturation of 88% during exercise training should be assessed. This can be done by trialling oxygen (2-4L/min) during the exercise that causes desaturation, and observing the response
  • The exercise program should be modified accordingly. Desaturation during small muscle mass exercise (e.g., arm exercise) is not common. Cycling often induces less oxygen desaturation than walking in patients with COPD

Supplementary oxygen in patients with chronic lung disease is provided mainly for safety reasons and to decrease the work of the right heart (i.e., by minimising hypoxic vasoconstriction of the pulmonary vessels).

For more detailed information see The Australian Lung Foundation Pulmonary Rehabilitation Toolkit

Exercise prescription for patients with pulmonary artery hypertension (PAH) must be individualised based on current medical management, status of PAH-specific medications and other co-morbidities that would impact on the individual's ability to undertake exercise. Current evidence supports exercise in NYHA functional class II, III, and IV.

Exercise in patients with PAH:

  • Improves cardiovascular fitness
  • Improves right and left ventricular function
  • Reduces pro-inflammatory cytokines
  • Improves peripheral muscle function

Evidence currently supports aerobic exercise including walking, exercise bike and treadmill; and low resistance training.

A rating of perceived exertion of 11-13 on the Borg scale, or 3-4 on the modified Borg scale, is recommended to monitor exercise intensity. Interval training regimens are recommended to avoid marked increases in pulmonary pressures with exercise. High-intensity exercise, isometrics and Valsalva manoeuvres are to be avoided.

The exercise clinician should monitor:

  • Oxygen saturation during exercise – aiming to maintain SpO2 above 85%
  • HR response – if bradycardia is observed during exercise, the patient should cease exercising and should be monitored. Recommencement of exercise should be carried out with caution and medical advice should be sought if necessary
  • Evidence of right HF

Following implantation of an implantable cardioverter defibrillator (ICD) or pacemaker, patients should avoid elevating the arm above 90 degrees for up to 4-6 weeks to allow the wires to embed within the endocardium. This time frame may vary depending on the cardiologist and local protocols. Upper limb resistance exercise should be avoided for 6 weeks.

Patients with ICDs are at risk of receiving inappropriate shocks during exercise if the HR increases to the zone at which therapies are programmed. Therefore, exercise should be planned to maintain the HR at least 10-15 beats per minute below the threshold. Contact sports must be avoided; it is particularly important to remind young people of this.

A diagnosis of ischaemic heart disease (IHD), including exertional or unstable angina, ST segment elevation myocardial infarction (STEMI) or non-ST segment elevation myocardial infarction (NSTEMI), involves a broad range of risk; therefore, exercise prescriptions should be developed on an individual patient basis. The appropriate mode and intensity of exercise is based on clinical risk and effort/exercise tolerance.

When assessing risk, the following should be considered:

Volume of infarcted myocardium (troponin rise)

  • Degree of ventricular impairment – on echocardiogram, refer to left and right ventricular function, and whether regional wall motion is hypokinetic or akinetic. On angiogram, refer to left ventriculogram
  • Region of infarcted myocardium – anterior vs inferior, apical vs basal
  • Potential for current or future ischaemia – other untreated stenoses or risk of restenosis
  • Type of intervention (angioplasty only vs drug eluting stent vs bare metal stent) – this can determine risk of future restenosis of the treated segment
  • Location of stenosis and the volume of myocardium effected
  • Inability to treat an occlusion, or a failed revascularisation

TIP: Individuals with good exercise tolerance or who demonstrate no symptoms on exertion can still be at significant risk. Exercise prescription should consider clinical risk, not just exercise tolerance.

Moderate-to-large myocardial infarctions require lower-intensity exercise in the first 4 weeks to allow for remodelling of the infarcted area, recovery of hibernating myocardium and reduction in risk of ventricular wall rupture. This applies to those with significant troponin rise, moderate-to-severe impairment of ventricular function or resting wall motion abnormalities at the time of the infarction.

While angiograms are extremely valuable in stratifying risk, the severity of a stenosis does not predict the risk of myocardial infarction (MI). Approximately 65% of MI's occur in arteries that are <50% occluded; 20% in arteries 50-70% occluded and 15% in arteries that are >70% occluded.[#falk-e-shah-pk-fuster-v.-1995]

Patients with ischaemia or coronary artery occlusion for ‘medical management’ may vary in risk. Medical management refers to the use of medications to affect the stenosis progression and minimise the likelihood of ischaemia or symptoms.

The decision to avoid procedural intervention may indicate:

  • Occlusion is not significant enough to require revascularisation
  • Small calibre vessel is not suitable for PCI
  • Small calibre vessel affects an insignificant volume of myocardium
  • Failed or aborted attempt to revascularise
  • Collateral circulation supplies the myocardium distal to the stenosis
  • Chronic total occlusion (i.e., there may be distal ischaemia)
  • Majority of myocardium distal to the stenosis is necrotic

TIP: The intention to ‘treat medically’ without intervention does not necessarily imply the absence of myocardial ischaemia or that the individual is at low risk.

All available clinical information (angiogram, myocardial perfusion scan, stress echo) should be reviewed to determine the following:

  • Location of the stenosis
  • Volume of myocardium distal to the stenosis
  • Likelihood of collateral circulation (where the area distal to the stenosis is supplied by other vessels)
  • Likelihood of ischaemia (perfusion defect or regional wall motion)
  • Maintenance or decline in left ventricular function on exertion

On an ongoing basis, it is important to determine whether:

  • Prescribed medication is providing symptomatic relief
  • Medications are well tolerated (i.e., side-effects)
  • ‘Medical management’ requires review to ensure it is achieving the desired outcome

Monitoring the patient’s response to exercise is essential.

TIP: Always reinforce the appropriate use of anti-anginal medications (glyceryl trinitrate; GTN) in patients who may experience angina. See section on exertional angina.

Myocardial infarction (MI) is associated with a broad array of clinical risk, with management depending on presenting features. Some form of revascularisation intervention is usual. The level of troponin released upon myocardial damage reflects the size of the infarct. This is often in keeping with the degree of ventricular dysfunction or wall motion abnormalities at the time of admission. This may improve over the first 4 weeks as ‘stunned’ myocardium restores its function, although detrimental remodelling may occur, leading to no improvement or even worsening HF.

Thorough screening and risk stratification are crucial; see previous section on ischaemic heart disease.

TIP: During hospital admission, sometimes only the culprit lesion will be revascularised, postponing treatment or reassessment of other stenoses for a later time, typically, 4-6 weeks.

Exercise prescriptions should commence at a low, well-tolerated level and progress gradually. The duration of exercise should progress before the intensity to avoid excessive load on the myocardium via increased HR and BP.

Larger infarcts with some degree of ventricular dysfunction or wall motion abnormality require greater precaution and slower graduation of exercise. Small infarcts with preserved myocardial function and no other stenosis allow exercise progression with less restriction.

Percutaneous coronary intervention (PCI) is where coronary stenosis treatment occurs via peripheral arterial access, usually the superficial femoral or brachial artery. It includes angioplasty (‘ballooning’) or percutaneous transluminal coronary angioplasty (PTCA), stenting or atherectomy (rotational atherectomy or rotablation).

When prescribing exercise in patients with recent PCI, the following should be considered:

  • Type of PCI and the risk of restenosis
  • Discomfort at rest or on exertion at, or distal to, the site of peripheral artery cannulation
  • Presence of angina symptoms at rest or on exertion
  • The patient's compliance with anti-platelet medications.

Most patients can resume physical activity and exercise within a few days of their PCI unless obvious problems are evident. The underlying IHD is the main influence on exercise prescription; see previous section on ischaemic heart disease.

Coronary artery bypass graft (CABG) is usually performed via surgical division of the sternum (i.e., median sternotomy). Post-operative complications include musculoskeletal problems related to the incisional scar (infection, hypersensitivity, hypertrophy) and sternal instability. Thorough assessment of these post-surgical factors is crucial to safe and effective exercise prescription.

Microvascular, or small vessel, coronary artery disease (CAD) involves the arterioles and capillaries that perfuse the heart muscle. Large vessels and branches may still be patent on coronary angiography.

Microvascular disease is treated medically, so exercise considerations are identical to ischaemic heart disease for medical management.

Medical management with pharmacological agents aims to:

  • Increase myocardial blood supply using vasodilators (nitrates and some calcium channel blockers)
  • Reduce cardiac oxygen demand by lowering HR and BP (beta-blockers and antihypertensives)
  • Prevent angina by promoting vasodilation or altering the myocardial oxidative metabolism.

It is important to clarify which medications have been prescribed to the patient to reduce myocardial ischaemia, and the time they are taken in relation to exercise. Some medications, particularly nitrates, have an 8-10 hour duration of effect, but typically take 1-1.5 hours to generate a therapeutic effect. The timing can affect safety and symptomatic benefit of these medications during exertion.

TIP: Educate patients about the timing and duration of their anti-anginal medications to ensure patient confidence and safety so that they can exercise safely.

Typical characteristics of angina symptoms should be assessed, including:

  • How the patient senses their angina (chest, back, arm, shoulder, jaw)
  • Type of activities/intensity of exercise that typically produces angina
  • How the patient resolves the symptoms (rest, GTN)
  • Severity of discomfort (scoring system out of 10)

TIP: When reviewing exercise tests, establish whether ischaemic ECG changes are accompanied by symptoms. A patient is at greater risk if ECG changes occur in the absence of overt symptoms.

The volume and territory of the possible ischaemia should be determined. A larger volume of affected myocardium implies a greater risk, as does anterior ischaemia compared with inferior wall ischaemia.

The following strategies can be considered to reduce physiological demand:

  • Prescribe exercise using less volume of muscle mass – rowing ergometer > cycling > unilateral leg extension
  • Prescribe small bouts of exercise with periods of rest – weight resistance or brief aerobic exercise
  • Reduce the intensity of exercise
  • Use prophylactic GTN

An important component of each exercise session is a warm-up and cool-down. Patients with exertional angina benefit from a very prolonged and gradual warm-up.

Prophylactic use of GTN

In consultation with the treating doctor, GTN can be used before or during exercise to prevent myocardial ischaemia.

Prophylactic GTN dilates the vasculature, increasing blood flow to the myocardium prior to the onset of symptoms. However, this systemic vasodilation may also reduce BP to the point of hypotensive symptoms. Therefore, BP should be recorded before and after GTN administration, both in a seated and standing position. Maximum dilation from GTN will occur within 5 minutes.

Implantation of ventricular assist devices (VADs) increase circulating blood flow and allow the patient to undertake exercise at a higher intensity. Maximal intensity, however, is sometimes limited by the device itself. Clinicians prescribing exercise should therefore have a thorough understanding of the physiology imposed by different devices.

Exercise considerations for patients fitted with a VAD include:

  • Being prone to post-surgical complications (bleeding, infection, respiratory compromise)
  • Often being extremely deconditioned following implantation, but can progress rapidly once post-surgical complications are resolved
  • Drive line infections being common and limit some exercises
  • VAD hardware (drivers, batteries, drive lines) restricting certain activities, although most activities can be modified to accommodate these. Aquatic activities are not appropriate
  • VADs having a system of alarms, some of which require urgent attention. The exercise supervisor should be familiar with their implications for exercise. VAD parameters should be recorded before and after each exercise session and any alarms that are triggered should be documented. In some circumstances, the VAD settings may require alteration, necessitating close liaison with the VAD nurse.

Exercise training is essential to optimise functional ability and fitness prior to transplant surgery, and to accelerate recovery in the post-operative phase. The pre-transplant phase may require shorter duration activities and greater rest periods. Exercise training also helps offset the effects of immunosuppressive medication (muscle atrophy, bone demineralisation, increased adiposity) and assists return to routine life following transplantation.

Patients need to contend with post-surgical complications, episodes of cardiac transplant rejection, altered physiology (cardiac denervation) and infection risk, so exercise should be prescribed and progressed according to individual circumstances and clinical presentation, to enhance continued and prolonged adherence.

  • American College of Sports Medicine. ACSM's Guidelines for Exercise Testing and Prescription. 9th ed. Philadelphia, PA: Lippincott Williams & Wilkins. 2013.

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  • Durstine JL, Moore G, Painter P, et al (Eds). ACSM’s exercise management for persons with chronic diseases and disabilities. 3rd Edition. American College of Sports Medicine. Champaign, IL: Human Kinetics. 2009.

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  • Hordern M, Dunstan D, Johannes P, et al. Exercise prescription for patients with type 2 diabetes and pre-diabetes: A position statement from Exercise and Sports Science Australia. J Sci Med Sport 2012;15:25-31.

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  • Colberg SR, Sigal RJ, Fernhall B, et al. Exercise and type 2 diabetes. The American College of Sports Medicine and the American Diabetes Association: joint position statement. Diabetes Care 2010;33:e147–e167.

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  • Falk E, Shah PK, Fuster V. Coronary plaque disruption. Circulation 1995;92:657-671.

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