| Δ0 | wearing socks while sleeping itself | wearing socks to bed |
| Δ1 | other sleepwear and bedding choices affecting body temperature | wearing gloves to bed, wearing a hat to bed, sleeping under a heavy comforter, wearing thermal pajamas |
| Δ2 | other bedtime devices used to add warmth | electric blankets, heated mattress pads, hot water bottles, space heaters in the bedroom |
| Δ3 | general sleep-hygiene habits and routines | screen time before bed, room lighting at night, caffeine before bed, going to bed at inconsistent times |
| Δ4 | everyday clothing choices unrelated to sleep | wearing socks during the day, wearing gloves outdoors, wearing a scarf in winter, wearing sandals in summer |
| Δ5 | general lifestyle and wellness habits unrelated to clothing or sleep | daily diet choices, exercise routines, hydration habits, vitamin supplements |