Our nails naturally develop slight vertical ridges as we age. However, severe and raised ridges can be a sign of iron deficiency anemia. Nutritional deficiencies, such as a lack of vitamin A, vitamin B, vitamin B12 or keratin can result in fingernail ridges. Hormonal changes can also cause ridges to appear.
Transient fatigue is acute fatigue brought on by extreme sleep restriction or extended hours awake within 1 or 2 days. Cumulative fatigue is fatigue brought on by repeated mild sleep restriction or extended hours awake across a series of days. Circadian fatigue refers to the reduced performance during nighttime hours, particularly during an individualâs âwindow of circadian lowâ (WOCL) (typically between 2:00 a.m. and 05:59 a.m.).