Physiological Responses

The goal of this study is to understand how caffeine and alcohol affect the ocular and physiological systems, especially how the pupil (the aperture in the colored part of the eye) responds to light. It will also test whether these changes can be used to detect recent caffeine or alcohol intake using a portable eye device. The main questions it aims to answer are: 1. How does caffeine change pupil responses, eye movements, and other ocular and physiological measurements? 2. How does alcohol change these same ocular and physiological responses? 3. Are the effects of caffeine and alcohol different from each other? 4. Can these changes be used to accurately identify whether someone has consumed caffeine or alcohol? Researchers will compare caffeine, alcohol, and a placebo (a look-alike drink with no active substance) to see how each affects the ocular and physiological outcomes. Participants will: 1. Attend three separate sessions where they will consume caffeine, alcohol, or a placebo (in random order) 2. Undergo pupillary response evaluation using a handheld device that measures responses to different colored light stimuli 3. Have their eye movements analyzed 4. Have retinal and choroidal thickness, blood perfusion, and ocular oxygen levels measured 5. Have basic body measurements recorded (such as pulse rate and blood pressure) 6. Complete tests at multiple time points over 2 hours after consumption The results of this study may help develop a quick and non-invasive way to detect recent caffeine or alcohol use for clinical and safety purposes.

The goal of this clinical trial is to learn how older adults respond to power training when the level of fatigue during exercise is different. Power training means performing fast movements with moderate loads to improve strength, power and mobility. The main questions the study aims to answer are: * How does the level of fatigue during power training acutely affect strength, movement, and muscle function? * How does it affect recovery, muscle soreness, and how hard the exercise feels? Researchers will compare three power-training sessions with different fatigue levels to see which approach may be safest and most effective for older adults. Participants will be healthy older adults aged 65 to 85 years. Each participant will complete three supervised exercise sessions on a leg press machine. The sessions will take place about one week apart. During the study, participants will: * Perform power training on a pneumatic leg press machine * Complete strength and mobility tests before and after exercise * Provide small blood samples to measure body responses to exercise * Rate how hard the exercise feels * Report muscle soreness for up to two days after exercise The results may help researchers design safer and more effective power-training programs to improve strength, mobility, and recovery in older adults.

The study aims to characterize the vascular response upon topical application of cinnamaldehyde, allyl isothiocyanate and capsaicin on feet skin in healthy volunteers. The vascular response will be characterized in terms of response over time, dose-response, inter-foot and inter-period reproducibility.