GPT-5.5 vs GPT-5.6 Terra for research skills

Overall, the evidence suggests short sleep is associated with a higher risk of infections such as colds, but it does not prove that lack of sleep directly causes them. A large 2021 study found adults sleeping under 6 hours had about 20% higher cold rates over 5 years, and a 2023 review found a broadly consistent link across 40 studies. However, a smaller 2019 student study found no significant relationship, showing the effect may vary by population, measurement, or study power. A major caveat is confounding: stress could plausibly reduce sleep…

Across the evidence, short sleep is associated with a higher risk of infections, especially colds, but the size and certainty of the effect remain unclear. The largest individual study found that adults sleeping under six hours had about 20% higher cold rates over five years. However, a smaller student study found no significant relationship, so results are not uniform across populations or study designs. A 2023 review of 40 studies concluded that the overall association is consistent, but also noted a major limitation: stress may both reduce s…