Heart disease
Excessive strain on the heart during hot weather may bring about dizziness, collapse, heart attack or stroke.
Lung disease
Warmer temperatures have been associated with worse symptoms in people with chronic lung disease. Breathing difficulties may also put excessive strain on the heart during heat exposure. People diagnosed with cystic fibrosis may also have increased salt loss from sweating.
Diabetes
Damage to blood vessels and nerves as complications of diabetes may impair the body’s mechanisms to regulate temperature. People with diabetes can also get dehydrated more quickly.
Kidney disease
Kidney disease may impact the body’s response to changes in blood pressure and to dehydration due to heat exposure.
Mental illness
Warmer temperatures have been associated with increased mental health risks including increases in self-harm and hospital admissions.
People with pre-existing mental illness may be at increased risk during periods of high temperatures due to social isolation and complex health conditions. In addition, antipsychotic medications may impair the body's ability to regulate temperature. Particular attention should be paid to identifying people with mental illness who may require assistance during times of prolonged high temperature.
Neurological diseases
Heat exposure may worsen some neurological conditions like multiple sclerosis or spinal cord injury because they can impact the body’s ability to regulate body temperature.