The theory behind them
Weighted blankets work on the principle of deep pressure stimulation - similar to the sensation of a firm hug or swaddling. This is thought to reduce activity in the sympathetic nervous system (the 'alert' state) and increase serotonin and melatonin production.
What the research actually shows
Studies show the clearest benefit for people with anxiety or sensory processing differences, where deep pressure stimulation has a more established calming effect. For general insomnia in an otherwise healthy sleeper, evidence is more mixed - some studies show modest improvements in sleep quality and reduced nighttime movement, others show little difference from a standard blanket.
Who tends to benefit most
- People with anxiety, particularly around bedtime
- People who describe themselves as restless sleepers
- People who already find firm pressure (tight sheets, being held) calming
- Less consistently beneficial for people who run hot at night, since weight can trap heat
Getting the weight right
The general guideline is roughly 10% of body weight, though personal preference varies considerably. Too heavy and it becomes restrictive rather than calming; too light and the pressure effect is lost entirely. If possible, trying one before committing (or checking a generous return policy) is worth it given how personal the preference is.