In a new study, scientists said that during the 2019 heatwave, hot temperatures and global warming were closely linked with weight loss in heart failure patients, indicating a worsening of their condition.
The study has focused on a relationship between ambient temperature and body weight in heart failure patients.
Professor Francois Roubille of Montpellier University Hospital, France, author of the study stated, "The weight loss we observed in people with heart failure may lead to low blood pressure, especially when standing up, and renal failure, and is potentially life-threatening. With rising temperatures forecast for the future, clinicians and patients should be ready to reduce the dose of diuretics when weight loss occurs".
Heart failure symptoms:
The study said that when a heating failure happens in a patient, the heart does not pump blood around the body, and waste products accumulate, causing shortness of breath and fluid build-up in the lungs, legs, and abdomen. Weight is the cornerstone of monitoring because weight gain is related to congestion, the main reason for the hospital admission.
How does diuretic help?
Diuretics, also called water pills, are used to increase urine output and reduce breathlessness and swelling. According to the European Society of Cardiology (ESC), patients need to be educated about increasing their diuretic dose or alert their healthcare team if they experience an increase in breathlessness or swelling or a sudden unexpected weight gain of more than 2 kg in three days.
Professor Roubille explained: "When healthy people drink more fluids during hot weather, the body automatically regulates urine output. This does not apply to patients with heart failure because they take diuretics."
How the study was conducted?
The analysis included 1,420 patients with chronic heart failure. The median age of the participants was 73 years, 28% were women, and the average weight was 78 kg.
The study examined the relationship between body weight and air temperature between 1 June and 20 September 2019, which covered the two heatwaves at the end of June and the end of July.
Patients weighed themselves every day using a connected weighing scale that automatically sent measurements to the clinic. Patients reported daily symptoms such as oedema, fatigue, breathlessness, and cough by answering questions on a personal device (e.g. smartphone, tablet), with answers sent automatically to the clinic.
The relationship between temperature and weight was very strong, with weight dropping as the temperature rose.
Professor Roubille said: "The weight loss we observed during the heatwave was clinically relevant. Patients weighing 78 kg lost 1.5 kg in a short period. We were surprised to see that weight dropped with hot temperatures, as we had expected the opposite.
He added a good rule of thumb would be to contact a healthcare professional if the weight drops by 2 kg during a heatwave for advice on adjusting diuretic medication.
