Memory foam can trap heat and cause night sweats, but simple steps can keep your memory foam mattress cool and prevent overheating. Breathable Bed Sheets - Buy bed sheets made from breathable materials, like cotton, Tencel, and linen. These sheets allow heat to escape instead of getting trapped and causing night sweats. Pajamas - Wearing cotton pajamas may prevent your body from retaining heat. Cotton is naturally breathable and wicks away moisture for a good night’s sleep. Mattress Topper - Adding a mattress topper not only adds softness or firmness to your current mattress but may keep you cool at night. Many mattress toppers may contain gel memory foam or down feathers. Gel absorbs and disperses body heat, while down feathers provide more airflow.