The breakdown of stored fat is ignited by nerves in the fat tissue, which gets upregulated by the hormone leptin. In mice, the absence of leptin shrinks neurons, which reduces the ability to burn fat.

Age-related hearing loss (presbycusis) is caused mainly by damage to hair cells, the sensory cells of the inner ear; the damage comes from loud noises and may benefit from hair cell regenerative therapy.

Genes linked to aging explain why people age at different rates. In data from over a million people, people with genes linked to longevity also had overrepresented genes linked to iron metabolism.

Cultivating happiness and gratitude leads to better physical health outcomes, including fewer sick days and improved subjective measures of well-being over a 3-month study period.