Low Blood Pressure

Low blood pressure (hypotension) is generally defined as blood pressure below 90/60 mmHg. Unlike high blood pressure, low BP is only a concern when it causes symptoms or is caused by an underlying problem. Many healthy young adults — especially women and athletes — have "normally" low readings and are perfectly fine.

Types

• Orthostatic (postural) hypotension — blood pressure drops when standing up; causes dizziness or faintness on rising
• Neurally-mediated hypotension — drop in blood pressure after standing for long or in response to triggers (stress, sight of blood)
• Low blood pressure from medical causes — dehydration, blood loss, severe infection, heart problems, endocrine disorders

Symptoms — when it matters

• Dizziness, lightheadedness
• Fainting
• Blurred vision
• Nausea
• Fatigue
• Cold, clammy skin
• Rapid shallow breathing
• Confusion (in older adults)

When low BP is an emergency

Very low BP with severe symptoms can signal shock — a life-threatening drop in blood flow to organs. Dial 112 for:

• Severe weakness, collapse, or unconsciousness
• Cold, pale, mottled skin
• Fast weak pulse
• Severe confusion
• Bleeding, severe vomiting/diarrhoea with very low BP
• Low BP with chest pain or breathlessness

Causes

• Dehydration — common in Indian summers
• Severe blood loss
• Severe infection (sepsis)
• Heart conditions — heart attack, heart failure, arrhythmias
• Endocrine problems — adrenal insufficiency, thyroid, low blood sugar
• Severe allergic reaction (anaphylaxis)
• Pregnancy — BP commonly lower in the first and second trimesters
• Medicines — blood-pressure drugs, diuretics, some heart medicines, antidepressants, drugs for Parkinson's, some cold medicines
• Ageing — autonomic nervous system changes
• Prolonged bed rest

Management

• Stay hydrated, especially in hot weather — water, ORS, nimbu-pani, coconut water
• Stand up slowly from lying or sitting
• Compression stockings for postural hypotension
• Small frequent meals (some people feel faint after large meals)
• Review medicines with your doctor if you suspect they're the cause
• Treat underlying causes — infection, bleeding, heart conditions
• Medicines (occasionally) for specific types of chronic low BP
• Salt — moderate increase sometimes helps, but discuss with a doctor (particularly if you have heart or kidney disease)

See a doctor if you have repeated dizziness, fainting, or low readings that worry you — especially with other symptoms. Routine investigation — blood tests, ECG, sometimes tilt-table testing — identifies most causes.