Bathtubs filled with frigid water and occasionally dotted with ice cubes are a common sight in professional athletes’ training rooms and at some gyms. Many recreational athletes also slip into cold baths at home after intense workouts.

But soaking in icy water after lifting weights can change how muscles respond to the workout and result in less muscle growth than doing nothing to recover, according to a cautionary new study of young men and their muscles. The study underscores that how we opt to recover from exercise may influence what we gain from the exercise and in sometimes unintended ways.

Almost no one claims that nippy baths are pleasant; the iciness tends to be pin-prickingly uncomfortable. But adherents believe the frigid waters reduce soreness and inflammation in muscles after draining exercise, lessen muscle damage, allow people to return to full training sooner, and encourage changes within the tissue that contribute to hypertrophy, which is the formal name for muscle growth.

There have been scientific hints in recent years, however, that icy baths after exercise might not be working in the ways that most icy bathers anticipate. Some studies found no differences in muscle and performance gains between athletes who soak after exertions and those who do not. And at least one experiment suggested that any positive physical impacts from cold soaks resulted from the placebo effect.