Morbidity and mortality have been increasing among middle-aged and young-old Americans since the turn of the century. We investigate whether these unfavorable trends extend to younger cohorts and their underlying physiological, psychological, and behavioral mechanisms. Applying generalized linear mixed effects models to 62,833 adults from the National Health and Nutrition Examination Surveys (1988-2016) and 625,221 adults from the National Health Interview Surveys (1997-2018), we find that for all gender and racial groups, physiological dysregulation has increased continuously from Baby Boomers through late-Gen X and Gen Y. The magnitude of the increase is higher for White men than other groups, while Black men have a steepest increase in low urinary albumin (a marker of chronic inflammation). In addition, Whites undergo distinctive increases in anxiety, depression, and heavy drinking, and have a higher level than Blacks and Hispanics of smoking and drug use in recent cohorts. Smoking is not responsible for the increasing physiological dysregulation across cohorts. The obesity epidemic contributes to the increase in metabolic syndrome, but not in low urinary albumin. The worsening physiological and mental health profiles among younger generations imply a challenging morbidity and mortality prospect for the United States, one that may be particularly inauspicious for Whites.