Altitude fatigue commonly develops when the body is exposed to reduced oxygen pressure at higher elevations. Lower atmospheric oxygen availability may decrease oxygen saturation in the blood, reduce aerobic energy production, alter vascular tone, and increase metabolic stress on tissues with high oxygen demand such as skeletal muscle and the brain. Fatigue at elevation is often associated with impaired mitochondrial energy generation, dehydration, electrolyte imbalance, reduced nitric oxide signaling, increased oxidative stress, altered circulation, and shifts in respiratory compensation mechanisms. As oxygen availability decreases, the body attempts to adapt through changes in ventilation, blood flow regulation, red blood cell signaling, and nitric oxide-mediated vascular responses. Reduced nitric oxide bioavailability may impair vasodilation and oxygen delivery efficiency, contributing to muscle heaviness, exercise intolerance, headache, slowed cognition, and generalized exhaustion. Increased respiratory water loss at altitude may also increase dehydration risk, especially during physical activity, cold weather exposure, or inadequate fluid intake. Oxidative stress pathways are commonly activated during altitude exposure due to mitochondrial strain and fluctuating oxygen tension. Increased reactive oxygen species production may affect endothelial function, circulation efficiency, cellular hydration regulation, and mitochondrial respiration. Individuals may also experience appetite suppression, reduced carbohydrate utilization efficiency, and disrupted electrolyte balance that further contribute to low energy levels and exercise fatigue. A whole food plant-based dietary pattern rich in nitrate-containing vegetables, potassium-rich fruits, hydrating foods, antioxidant-rich berries, mineral-containing legumes, and polyphenol-rich plants may help support oxygen delivery, endothelial function, hydration balance, mitochondrial efficiency, and circulatory adaptation during altitude exposure. Naturally occurring dietary nitrates from beetroot, arugula, spinach, celery, and watercress may support nitric oxide production pathways involved in vascular flexibility and oxygen transport regulation. Foods rich in vitamin C compounds, flavonoids, carotenoids, anthocyanins, potassium, magnesium, and polyphenols may help support antioxidant defense systems, endothelial resilience, hydration stability, and cellular energy pathways associated with altitude adaptation. Hydrating fruits such as watermelon, orange, kiwi, and pomegranate may also support fluid balance and potassium replenishment. Complex carbohydrate sources including oats, quinoa, lentils, and brown rice may help support glycogen availability and mitochondrial energy production during increased metabolic stress associated with high elevation environments.