Cold therapy may be worse than doing nothing for post-exercise recovery

Ice baths are popular after a strenuous workout WOJTEK RADWANSKI/AFP via Plunging into an ice bath after a workout may be worse for your muscle recovery than doing nothing. Cold therapy is a popular intervention after rigorous exercise, like marathons, to relieve soreness and dampen the inflammation that can impair muscle recovery. But in a new study, adults who had ice baths after intense leg exercise showed markers of muscle damage for longer than those who just rested. “Ice baths have long been considered a go-to recovery strategy in sport, so many people might expect them to outperform doing nothing,” says Freya Bayne at the University of East London. But emerging studies suggest that cold therapies slow muscle-protein synthesis . “The [latest] study contributes to a growing conversation that recovery strategies should be selected based on the desired outcome, rather than assuming one approach works for everything,” she says. The use of cold therapy – from ice baths and cold showers to open-water swimming – dates back centuries. Some studies suggest that cold therapy, particularly if it involves open-water swimming, benefits our mental health. But other claims, such as those made , lack good scientific evidence. Focusing on muscle recovery and soreness, Bayne and her colleagues compared cold therapy with other post-exercise interventions. Forty adults who regularly strength-train had the strength of their quadriceps measured via a machine that also controls movement. While seated, the participants pushed against the machine as hard as possible while it kept their knee in a fixed position. They then performed a high-intensity knee-extension exercise using the same leg. This involved them trying to straighten their knee as much as possible while the machine pushed it back towards a bent position, causing the quadriceps to lengthen. Similar movements occur when lowering into a squat or running downhill. These can cause small tears to muscle fibres, which trigger an inflammatory response and lead to muscle soreness. This discomfort usually kicks in within hours of doing a new or particularly intense workout, peaking between 24 and 72 hours, and fading after a week. Straight after exercising, the participants’ muscle strength was measured again, revealing a loss of 36 per cent, on average. They were then randomly assigned to one of four recovery strategies: cold-water immersion at 9°C (48°F) for 15 minutes, hot-water immersion at 42°C (108°F) for 30 minutes, hot-air exposure at 30°C (86°F) for 30 minutes, or passive rest at room temperature for 30 minutes. Cold-water immersion is typically a short treatment to reduce the risk of hypothermia, which is why it was offered for just 15 minutes.