Kidney disease, diabetes, inflammation and infection of the urinary and genital tracts may cause urine to smell bad. The body produces less urine at night, so it is a normal physiological phenomenon that some people wake up early with yellowish urine and a heavy smell, but most have only a slight smell that is not particularly heavy, and if it is heavy, it is most likely considered to be related to disease.
Inflammation and infection of the urinary system can potentially lead to changes in the nature and smell of urine. If pathological factors induce foul-smelling urine, it will most likely be worse in the morning and the symptoms may not be relieved after appropriate increases in water intake, requiring symptomatic treatment before significant improvement can be seen.