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Brain Teaser

Challenge Your Cognitive Know-How!

By

Staying Sharp

Published October 05, 2026

Which body system is influenced by sunlight exposure?

Your circadian rhythm

Your digestive speed

Your muscle flexibility

Your sense of taste

Your circadian rhythm helps regulate when you feel alert and when you feel sleepy. Sunlight is one of the strongest signals that helps keep this internal clock on track. Learn more about the brain benefits of sunlight here.

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Legal Disclaimer: Staying Sharp, including all content and features, is offered for informational purposes and to educate users on brain health care and medical issues that may affect their daily lives. Staying Sharp is based on a holistic, lifestyle approach to brain health that encourages users to incorporate into their daily lives activities that are associated with general wellness. Nothing in the service should be considered, or used as a substitute for, medical advice, diagnosis, or treatment. Features including the Cognitive Assessment and Lifestyle Check-Ins, Additional Tests, exercises, and challenges assess performance at a particular moment in time on certain discrete cognitive tasks. Staying Sharp games are intended for entertainment and recreational purposes only. Various factors may affect performance, including sleep, tiredness, focus, and other social, environmental, or emotional factors. Performance is not indicative of cognitive health and not predictive of future performance or medical conditions.

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