As heat waves stretch on, many people notice bulging veins, swollen ankles or legs that feel unusually heavy and achy by day’s end. These are often early markers of chronic venous disease, a condition in which weakened vein walls and valves struggle to move blood efficiently back to the heart. Instead, blood pools in the lower legs, raising pressure in the veins and producing symptoms ranging from mild swelling to persistent pain and fatigue.
The condition is more common than many realize. While its overall prevalence isn’t precisely known, one long term study in Edinburgh found that varicose veins, a form of chronic venous disease, developed in nearly 10% of people ages 18 to 34 and just over a quarter of those ages 55 to 64 over a 13 year period. In its most severe form, the disease can lead to dangerous blood clots, and venous thromboembolism is estimated to cause 25,000 to 30,000 deaths annually in the United Kingdom.
Heat makes symptoms worse because the body dilates blood vessels to cool itself, allowing more blood to collect in the legs, which often results in throbbing or cramping, particularly for people who spend long stretches on their feet.
Who faces the greatest risk
Genetics appear to play a role, and people whose parents or grandparents experienced similar vein issues may be more susceptible, especially heading into midlife. Age is another major factor, since veins naturally lose elasticity over time while valves weaken, allowing blood to flow backward toward the feet rather than up toward the heart. Excess weight, particularly around the abdomen, adds further strain by forcing leg veins to work harder, which can gradually damage valve function.
How the condition progresses
Chronic venous disease exists on a spectrum, five stages patients may experience as the condition advances.
The mildest form, spider or thread veins, appears as small red, blue or purple web like patterns beneath the skin, caused by valves that allow blood to flow the wrong direction. They’re typically painless and considered cosmetic, though some people experience itching or burning. Treatments like sclerotherapy and laser therapy can address them, though these procedures usually aren’t covered by public health systems since they’re classified as cosmetic.
Next, rising pressure in the veins can cause capillaries to leak fluid into surrounding tissue, resulting in puffy ankles. Regular walking helps by encouraging calf muscles to pump blood back toward the heart.
Varicose veins, the third stage, are swollen and twisted veins visible beneath the skin, often accompanied by itching, throbbing and cramping that worsens throughout the day. Left untreated, they can cause skin discoloration and, eventually, slow healing ulcers. Treatment typically starts with an ultrasound scan followed by procedures to close off the affected veins.
If left unaddressed, varicose veins can progress to deep vein thrombosis, a serious and potentially life-threatening clot that requires urgent medical care. Symptoms include throbbing pain, swelling and discolored skin, and treatment generally involves blood thinning medication for at least three months alongside regular walking and leg elevation.
The most advanced stage, deep venous reflux, occurs when damaged valves in the deep leg veins cause blood to flow backward, leading to swelling, pain and non healing ulcers. Treatment centers on exercise, leg elevation and graduated compression garments, with the appropriate compression level depending on symptom severity.
Managing symptoms through the heat
Wilton recommends several strategies to ease symptoms during hot weather. Elevating the legs above hip height for 15 to 20 minutes several times a day helps reduce pressure in the deep veins. Staying well hydrated, aiming for roughly eight cups of water daily, prevents blood from thickening, which can make circulation less efficient, and she advises limiting dehydrating drinks like tea and alcohol.
A cool, damp compress applied to the legs can ease pain by gently constricting blood vessels and reducing inflammation. Light exercise, such as walking, gentle yoga or swimming in shaded or cool areas, also helps by encouraging calf muscles to move blood away from the legs, all while avoiding direct heat exposure that could worsen symptoms.
