Blood pressure (BP) is another factor that is directly affected by exercise. As with temperature, your body has a series of automatic mechanisms that work to keep your blood pressure in a safe range during and after exercise.
What Issues Are Posed With SCI?
Spinal cord injury, however, affects your body’s autonomic responses and its ability to regulate blood pressure. There are two conditions that individuals with a SCI need to be aware of during exercise – orthostatic hypotension and autonomic dysreflexia (AD).
Orthostatic hypotension is a drop in blood pressure when in an upright position.
Orthostatic hypotension occurs most frequently when:
- Changing from a lying position to a sitting position,
- Changing from a sitting position to a standing position, or
- Sitting or standing for long periods of time.
It occurs in these positions because blood pools in the legs. Furthermore, loss of nervous system control and muscle function in the lower body and trunk (typically associated with SCI) make it difficult for the body to pump blood from the legs to the brain.
Symptoms of orthostatic hypotension include:
If you experience any of these symptoms, lay on your back with your feet elevated until your symptoms go away.
How to Reduce Risk When Exercising
To reduce the risk of orthostatic hypotension when exercising you can:
- Gradually increase the pace and intensity of exercise to avoid sudden drops in blood pressure.
- Get up slowly. Avoid quickly moving from lying to sitting or from sitting to standing.
- Stay well hydrated before, during, and after exercise.
- Wear an abdominal binder and/or compression stockings to help move blood from the legs and trunk to the brain.
- Compression garments increase blood flow to the brain by increasing pressure in the trunk and lower extremities and “pushing” the blood towards the head.
Autonomic Dysreflexia (AD)
Autonomic Dysreflexia (AD), or autonomic hyperreflexia, is an extremely dangerous condition that results in very high blood pressures (up to 190 – 250 mm Hg systolic and 130 – 150 mm Hg diastolic) and is caused by an irritating stimulus, such as a full bladder, urinary tract infection, or pressure sore, below the level of injury. Individuals with a complete SCI at T6 or higher are most susceptible to AD since these individuals lack sensation in the lower extremities.
When irritation occurs below the level of SCI, the body reflexively responds by causing spasms and narrowing blood vessels, resulting in a rise in blood pressure. The body attempts to send signals to the brain about the increase in blood pressure; however, these signals are carried only as far as the spinal cord lesion and stop before reaching the brain.
Since the SCI lesion interrupts communication between the lower body and brain, the brain is unable to detect and respond to the increase in blood pressure. Unless treated, the blood pressure will continue to rise until it reaches potentially fatal levels.
Symptoms of Autonomic Dysreflexia include:
- High blood pressure (hypertension)
- Profuse sweating
- Shortness of breath
How to Reduce Risk When Exercising
To reduce the risk of autonomic dysreflexia when exercising:
Do not exercise if you:
- Have a urinary tract, kidney, or other infection.
- Have a known injury (e.g. broken bone) or wound (e.g. pressure sore) below the level of SCI.
- Are constipated.
Prior to your exercise session, always:
- Examine your body below the level of SCI for signs of injury or other potential irritants. Look for things such as pressure sores, bruises, blisters, and ingrown toenails.
- Empty your bladder and bowels.
- Make sure your urinary catheter is unobstructed and working properly.
If you begin experiencing any symptoms of AD during your workout, immediately:
- Stop exercising.
- Determine the source of the irritant and remove it, if possible.
- Sit upright to reduce blood pressure.
- Loosen any tight clothing.
If your symptoms do not get better right away after taking these steps, contact emergency medical services! Remember, AD is a very serious condition and getting medical care as soon as possible could be the difference between life and death.