Hypotension

Hypotension means low arterial blood pressure, but the number alone does not always mean disease. In some people, pressure around 90/60 mmHg or lower is habitual and causes no weakness, dizziness, or fainting. In others, even a moderate fall leads to darkening vision, unsteadiness, nausea, cold sweat, and fall risk. Hypotension is therefore assessed not only by the monitor but also by symptoms, circumstances, pulse, medications, fluid, salt, temperature, food intake, and coexisting disease.

Different situations

Acute hypotension is more dangerous than habitually low pressure. If pressure drops suddenly after bleeding, severe infection, dehydration, allergic reaction, heart attack, pulmonary embolism, or medication overdose, urgent care is needed. Fainting, confusion, cold clammy skin, chest pain, shortness of breath, severe weakness, black stool, vomiting, high fever, and marked tachycardia are warning signs. In such situations, drinking coffee and waiting is not enough.

Orthostatic hypotension occurs on standing, when blood vessels and the nervous system fail to maintain pressure quickly enough. A person may feel dizziness, darkening vision, weakness, or near-fainting within the first minutes after standing up. Causes include dehydration, low salt intake, prolonged bed rest, diabetic neuropathy, Parkinson disease, some antidepressants, blood pressure medications, diuretics, alcohol, and age-related autonomic changes.

How to measure and check

It is useful to measure blood pressure and pulse lying after rest, then standing after one, three, and sometimes ten minutes. The key is not only the pressure number but also pulse rise, symptoms, and repeatability. If pulse rises sharply without a large pressure drop, a clinician may consider other forms of orthostatic intolerance. If pressure falls together with symptoms, the cause should be sought: fluid, salt, blood loss, medications, endocrine disorders, heart function, and the nervous system.

Persistent symptomatic hypotension may require complete blood count, ferritin, electrolytes, glucose, TSH, cortisol when indicated, kidney function, ECG, medication review, and sometimes cardiology or neurology assessment. In young people, fainting is often vasovagal, but this does not mean every faint is harmless. Fainting during exertion, while driving, with chest pain, palpitations, or a family history of sudden death requires particular attention.

Nutrition, keto, and salt

On a low-carbohydrate diet, hypotensive symptoms can intensify in the first weeks because insulin falls, the kidneys excrete more sodium and water, and blood volume can temporarily decrease. This is one reason for weakness, dizziness, and palpitations in people who abruptly remove carbohydrates, eat too little, and fear salt. A gentler transition, adequate fluid, salt, broth, potassium- and magnesium-containing foods, sufficient protein, and enough calories may help.

Salt is not a universal medicine. In heart failure, kidney disease, severe hypertension, edema, and some medication situations, increasing salt can be harmful. If low pressure comes with weight loss, diarrhea, vomiting, skin darkening, salt craving, severe weakness, or low sodium, endocrine causes, including adrenal insufficiency, should be considered. On keto, not everything should be dismissed as adaptation.

Postprandial hypotension is a separate situation in which blood pressure falls after eating. It is more common in older adults, autonomic dysfunction, diabetes, and after very large meals. Symptoms appear within 30–90 minutes: sleepiness, weakness, dizziness, and unsteadiness. Smaller meals, more protein, fewer rapid carbohydrates, water before meals, and a short calm walk may help, but repeated episodes need medical assessment.

Hypotension should be distinguished from hypoglycemia. Both can cause shaking, weakness, and darkening vision, but measurements differ. If a person eats sugar for every dizzy spell, they may miss low pressure, dehydration, or a medication cause. When possible, measuring both blood pressure and glucose during symptoms is useful.

Practical help

For orthostatic symptoms, helpful measures may include standing up slowly, drinking water in the morning, eating enough protein at breakfast, using compression stockings when indicated, moving calf muscles before standing, and avoiding overheating. Large alcohol doses, sauna, hot showers, prolonged standing, and abrupt fasting can worsen symptoms. If a person takes blood pressure medication and pressure becomes too low after weight loss, dose review should be discussed with a clinician rather than enduring dizziness as discipline.