In healthy adults, the half-life of caffeine is around 3 to 4 hours. Half-life of caffeine depends on variables like liver function, enzymes level in the liver, age and pregnancy. Caffeine acts as competitive inhibitor of the enzyme cAMP-PDE in which it transforms cAMP to noncyclic form and enables cAMP to build up in cells. Caffeine may enhance the mood when the serotonin level is raised by acute usage of caffeine. Caffeine is classified as ergogenic as it can raise the physical and mental labor capacity (“About The Caffeine Molecule,” n.d.).
Caffeine is a highly consumed psychoactive drug which brings potential impacts on inhabiting organisms. Study of caffeine exposure for 28 days on Ruditapes philippinarum species indicates that the defense mechanisms increase with increasing caffeine concentrations. Increasing caffeine concentration diminishes the energy reserves which is the glycogen needed to counter oxidative stress. In addition, caffeine impacts on aquatic environment in which it triggers oxidative stress in bivalves organisms. Exposure of caffeine towards bivalves may cause peroxidation of polyunsaturated fatty acids in membrane due to the large amount of reactive oxygen species produced (Cruz et al., 2016).