Classification, Physiology and Thermoregulation in Para Sport

Classification groups athletes so that success reflects skill, fitness and tactics rather than the degree of impairment, and it is based on the impact of impairment on a specific sport, not on diagnosis. Under the International Paralympic Committee (IPC) framework, an athlete must have an underlying health condition leading to one of the eligible impairment types, which include impaired muscle power, impaired passive range of movement, limb deficiency or limb length difference, short stature, coordination impairments such as hypertonia, ataxia and athetosis, and vision or intellectual impairment. They must then meet the sport's Minimum Impairment Criteria (MIC), the least impairment that still affects performance, before being allocated a sport class by their activity limitation. Classification is evidence-based and sport-specific, carried out by trained classifiers who are relevant health professionals or technical experts. The SEM clinician's role is usually to supply accurate medical and diagnostic documentation, and intentional misrepresentation of ability is an integrity breach.

Impairment changes the body's response to exercise, most strikingly after spinal cord injury (SCI). The cardiovascular impact is greatest with a complete cervical or high thoracic injury, where disrupted sympathetic outflow blunts the normal rise in heart rate and blood pressure during exercise, limits peak heart rate, and, with loss of the muscle pump and sympathetic venoconstriction, reduces venous return, stroke volume and peak oxygen uptake. Tetraplegia is affected more than paraplegia, and orthostatic hypotension is common. Reduced active muscle mass also lowers maximal aerobic capacity. Heart-rate-based exercise targets may therefore be unreliable, and testing is interpreted against the athlete's own physiology. Amputation reduces muscle mass and alters the energy cost of movement, and a prosthetic socket can trap heat, while cerebral palsy affects movement efficiency through spasticity and impaired coordination. Knowing an athlete's impairment is the starting point for safe prescription.

A key emergency in para sport is autonomic dysreflexia (AD), which can occur in spinal cord injury at or above the sixth thoracic level. A noxious stimulus below the lesion, most often a full or blocked bladder, triggers a sudden rise in blood pressure, at least 20 mmHg above baseline systolic, with a pounding headache, flushing and sweating above the level; the pulse may be slow, normal or fast. Baseline systolic pressure in tetraplegia is often low, around 90 to 110 mmHg, so 130 to 140 mmHg can be a hypertensive emergency; untreated it can cause stroke or death. The immediate priorities are to sit the athlete upright, loosen anything tight, and find and remove the trigger, checking the bladder and catheter first, while monitoring blood pressure every 2 to 5 minutes. If pressure stays high, a short-acting antihypertensive is given, either sublingual glyceryl trinitrate (GTN) spray or nifedipine 5 to 10 mg bitten and swallowed, but only after checking for phosphodiesterase-5 (PDE-5) inhibitor use in the previous 24 to 48 hours, since a nitrate afterwards can cause life-threatening hypotension. Escalate urgently if the episode does not settle or systolic pressure exceeds 150 mmHg. Boosting, the deliberate induction of this response to gain an advantage, is dangerous and prohibited.

Spinal cord injury also impairs temperature control. Below the lesion, lost sympathetic control means reduced or absent sweating and impaired skin blood flow, so the body cannot dissipate heat in the heat or conserve it in the cold, and the impairment is greater with higher lesions. Reduced sensation below the level means the athlete may not feel themselves overheating. This raises the risk of exertional heat illness, greatest in tetraplegia, and of hypothermia in the cold. Amputation reduces the skin surface available for heat loss, and prostheses can trap heat. Cooling therefore has to be planned, using pre-cooling and cooling during activity or in breaks, with cold drinks or ice slurry, cooling garments, misting and fans, alongside hydration, heat acclimatisation, shade and sensible scheduling. In the cold, insulation and covering exposed and insensate limbs matter, since the athlete may not notice it.

Good care of the para-athlete starts before the event: knowing each athlete's lesion level and autonomic status, thermoregulatory risk, medication, pressure areas and a baseline blood pressure prepares the medical team. Heat and cold-weather planning, with cooling stations and clear thresholds for action, belong in the event medical plan. Heat illness is managed on standard lines with rapid cooling, but presentation can be atypical because the athlete may not sweat, so a high index of suspicion is needed. Cold water immersion for exertional heat stroke needs particular care in high SCI or tetraplegia: one-to-one airway monitoring for the drowning risk from impaired trunk and motor control, cervical support, and protection of insensate skin from pressure injury. If immersion is unsafe, aggressive alternative cooling is used, with rotating ice-water towels, ice slurry and cooling vests. Autonomic dysreflexia is recognised and managed as above, with early escalation. Pressure injuries and bladder and bowel care are ever-present, and this work is shared with classifiers, physiotherapists and coaches, escalating emergencies to urgent care with specialist input.

• •The International Paralympic Committee Athlete Classification Code sets the framework for eligible impairments, minimum impairment criteria and evidence-based, sport-specific classification.
• •Impaired cardiovascular and thermoregulatory responses after spinal cord injury, and their relationship to the level of lesion, are well described and underpin individualised exercise prescription and cooling.
• •UK spinal injury guidance on autonomic dysreflexia sets out its recognition and stepwise response, and the International Paralympic Committee prohibits boosting.
• •Cooling strategies, including pre-cooling and cooling during exercise, reduce thermal strain in athletes with spinal cord injury, though the optimal approach varies by individual and setting.

• •Para-sport classification is based on the impact of impairment on the sport, not on the diagnosis.
• •Cardiovascular impairment after spinal cord injury depends on lesion level and completeness, greatest with complete cervical or high thoracic injury, so heart-rate targets may be unreliable.
• •Autonomic dysreflexia is a hypertensive emergency at or above the sixth thoracic level; sit the athlete up and remove the trigger (usually a full bladder), and boosting is its prohibited deliberate induction.
• •Resting systolic pressure is lower in high spinal cord injury (around 90 to 110 mmHg), so a standard-normal reading can signal autonomic dysreflexia.
• •Screen for phosphodiesterase-5 (PDE-5) inhibitor use in the previous 24 to 48 hours before giving glyceryl trinitrate or nifedipine.
• •Spinal cord injury impairs sweating and skin blood flow below the lesion, raising heat illness and hypothermia risk, so cooling must be planned.