Her BP shot up to 208/110 mmHg despite walking 10,000 steps a day: How cold weather triggers silent hypertension and kidney risks

The stressed kidneys cause salt/water retention, leading to fluid overload and elevated BP, trapping Singhal in a vicious cycle. In fact, she had to be rushed to hospital one night as her systolic reading, which measures the pressure when your heart beats, crossed 208 and her diastolic count was 110. A BP of 180/120 mmHg is considered a crisis point.

For 56-year-old Mahendra Pratap, who was diagnosed with hypertension four years ago, winters have been about caution, having BP medicines at the same time everyday and keeping himself hydrated. “I keep myself under layers and have warm water,” he says. Both Singhal and Pratap need to keep extra warm and an elevated dose of medication every winter.

“Blood vessels constrict in lower temperatures, circulation slows and blood thickens slightly, all of which can push blood pressure upward,” explains Dr Tarun Kumar, senior director, Medanta Moolchand Heart Centre, who has got Pratap to maintain a drug and lifestyle discipline.

Why BP patients must be vigilant during winter

Dr Kumar says the heart has to work harder, starting with vasoconstriction, where blood vessels narrow to preserve body temperature. This directly raises blood pressure. “Then there are metabolic changes as people tend to eat more and reduce physical activity, which in turn lead to weight gain and poor blood sugar control. Reduced sweating during winter increases intravascular fluid volume, which further raises blood pressure. Another major concern is the higher risk of clot formation due to hormonal changes, reduced activity and clotting abnormalities, increasing the chances of thrombosis. Together, these changes increase blood pressure and put additional strain on the heart,” he says.

As a result, many patients with previously controlled blood pressure require higher medication doses. Some patients are diagnosed with hypertension for the first time after presenting with nasal bleeding or stroke. “Heart attack cases increase by about 20–30 per cent at my OPD during peak winter months, driven by uncontrolled hypertension, uncontrolled diabetes, increased cardiac strain and a higher risk of clot formation. About 40 per cent of patients coming to OPDs in winter have uncontrolled hypertension or complications such as nosebleeds, intracranial bleeding and severe headaches,” he says.

“Many people fail to notice rising blood pressure because hypertension is largely asymptomatic, especially in the early stages. Worst, those on medication tend to discontinue it once their levels are normal and have a rebound. BP medication needs to be taken at the same time everyday for consistency and ensuring the drug has stable levels which can in turn stabilise BP throughout the day,” he says.

The BP-kidney connection

Dr Mahajan says that patients who already have kidney disease are especially prone to hypertension. “During winters, many patients, who are well-controlled on a certain number of medications, may require an additional dose. If they do not monitor their blood pressure regularly, they may not realize it has increased. This can accelerate kidney disease,” he says.

However, those who track their blood pressure and report changes receive timely adjustments to their medication. “Starting October, we advise patients to monitor their blood pressure closely, even when on medication. Those who are unaware of this seasonal effect often face the most problems. If blood pressure rises in older adults, the chances of complications are higher,” says Dr Mahajan. He also highlights the importance of maintaining indoor physical activity during colder months.

Physical activity lowers blood pressure by strengthening the heart to pump more efficiently, reducing arterial stiffness, decreasing stress hormones, improving blood vessel function and managing weight. “Exercise strengthens muscles for better sugar use and helps filter waste more efficiently, slowing kidney disease,” adds Dr Mahajan.