Influence of lifestyle and the circadian clock on reproduction.

The biological reproductive process requires the precise coordination of annual and daily signals to adapt to environmental shifts. Humans and animals have developed shared neuroendocrine systems that have adapted to process daily and seasonal light signals within the hypothalamic-pituitary -gonadal axis. However, the stability of circadian and seasonal biological processes is at risk due to industrialization and contemporary round-the-clock lifestyles. These threats include skipping breakfast, excessive artificial illumination during inappropriate hours because of irregular work schedules, nighttime urban lighting, and widespread environmental pollution from endocrine-disrupting chemicals. This review aimed to explore the interplay between lifestyle factors, circadian rhythms, and reproductive functions. This review examined the reciprocal influences of circadian clocks on reproductive hormones, exploring the underlying mechanisms and their implications for fertility and reproductive health. We emphasized key findings regarding molecular clock components, endocrine pathways, and the critical importance of synchronizing circadian rhythms with hormonal cycles. The intersection of reproductive endocrinology and circadian biology reveals complex interactions between hormonal regulation and circadian rhythms. Circadian rhythm misalignments due to environmental factors, including late-night work and skipping breakfast, negatively impact endocrine and reproductive functions. More strategies are needed to mitigate the effects of circadian disruption on reproductive functions.