Nick NA/Shutterstock.comDoctors have long relied on measurements like body mass index (BMI) and waist-to-hip ratios to assess health risks. However, researchers are increasingly focusing their attention on an unexpected indicator: neck circumference.A thick neck might project strength, like that of heavyweight boxers or rugby players, but studies suggest it could signal a concerning health issue.BMI, which divides weight by height to estimate body fat, doesn’t always tell the complete story. A competitive bodybuilder might have a high BMI, but clearly isn’t obese. This is where neck circumference offers additional insight.Research shows that people with larger necks relative to their body size face increased risks of several serious health conditions. The connection lies in what neck size reveals about fat distribution, particularly in the upper body.This fat around your upper body releases fatty acids into your blood, which can interfere with how your body manages cholesterol, blood sugar and heart rhythm. Essentially, neck circumference serves as a proxy for visceral fat – the harmful fat that wraps around your organs.The evidence linking neck size to health problems is striking. People with thicker necks show increased rates of several cardiovascular diseases, including hypertension, atrial fibrillation and heart failure.Atrial fibrillation is particularly concerning. This condition causes irregular heartbeat and blood flow, potentially leading to blood clots and stroke. The electrical imbalance in the heart can eventually progress to heart failure.Neck circumference also correlates with coronary heart disease, where the main arteries to the heart narrow and restrict oxygen-rich blood flow.But cardiovascular problems aren’t the only concern. Larger neck circumference increases the risk of developing type 2 diabetes and gestational diabetes. Diabetes can lead to serious long-term complications, including vision loss and limb amputations.There’s also a connection to sleep disorders. Thick necks have been linked to obstructive sleep apnoea, where breathing repeatedly stops and starts during sleep. This condition causes extreme daytime fatigue and strains the cardiovascular system. People with sleep apnoea face higher risks of car accidents due to their exhaustion.So what constitutes a risky neck size? For men, 17 inches (43cm) or greater increases health risks. For women, the threshold is 14 inches (35.5cm) or greater.Perhaps most surprisingly, these risks persist even in people with normal BMI. You could have a healthy weight according to traditional measures, but still face elevated health risks due to neck circumference.And for each additional centimetre of neck circumference beyond these thresholds, death rates and hospitalisation rates increase.What this means for youIf your neck measures above these thresholds, it’s not cause for panic – but it is worth taking seriously. Neck size represents just one piece of your overall health picture, but it’s an important one that’s often overlooked.The good news is that neck circumference can change with lifestyle modifications. Cardiovascular exercise and weight training can help reduce upper-body fat. Quality sleep supports metabolic regulation and recovery. A balanced diet rich in pulses, fruits, and vegetables provides essential nutrients without excess calories.Measuring your neck takes seconds with a tape measure. Simply wrap it around the narrowest part of your neck, ensuring the tape is snug but not tight.This simple measurement could provide valuable insight into health risks that traditional metrics might miss. While neck circumference shouldn’t replace other health assessments, it offers another tool for understanding your cardiovascular and metabolic health.In an era where we’re constantly seeking better ways to predict and prevent disease, sometimes the answers are literally right in front of us. Your neck might be revealing more about your health than you realise – and it’s worth paying attention.The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.