Our goal is to determine whether hydration status influences inflammation, and overall physiological performance in adults aged 45-65. Aim 1: The effects of 4-day mild dehydration followed by 4-day rehydration (defined as approximately 2-3% body mass loss) on H2O2, upstream inflammatory signal (NFkB), mitochondrial fragmentation, and autophagy in circulating PBMCs. Aim 2: The effects of 4-day mild dehydration followed by 4-day rehydration (defined as approximately 2-3% body mass loss) on fasting glucose, sleep performance, and strength performance. Participant will: complete a 4-day hydration protocol, followed by a 4-day dehydration protocol, and then a 4-day rehydration protocol. attend five laboratory visits for testing: Day 1: Informed consent and familiarization Day 2: Pre-hydration testing (before the 4-day hydration protocol) Day 3: Pre-dehydration testing (before the dehyration protocol) Day 4: Post-dehydration testing (after the dehydration protocol) Day 5: Post-rehydration testing (after the rehydration protocol)