Table 4.

Various biological markers associated with numerous physical, emotional and environmental stresses.

S. No.	Biomarker molecule	Brief introduction	Efficacy of the molecule	Associated ailment(s)	Marker intended for	Diagnostic assay	Reference(s)
1.	α-amylase	A salivary enzyme, estimated as the marker for sympathetic stimuli. In stress response the α-amylase concentration increases	Hydrolysis of internal α-1,4-glycosidic linkages in starch	Stress associated with periodontal disease	Physiologic and behavioral stress	Enzyme Immunoassay (EIA) kit	Rai and Kaur, 2011
2.	Chromogranin A (CgA)	A protein prohormone with acidic nature, present in the secretory granules of different neuroendocrine tissues	Influence endocrine, cardiovascular, and immune systems and glucose or calcium homeostasis	Indicative of endocrine tumors, cardiovascular, inflammatory, and neuropsychiatric diseases	Mental stress marker during monotonous driving	ELISA, immunoradiometric assay (IRMA) and RIA	Yamakoshi et al., 2009; D'amico et al., 2014; Gut et al., 2016; Mishra, 2017
3.	Secretory IgA	Present in external body secretions like saliva. The induction of stress hormones, especially cortisol, have an adverse impact on immunoglobulin secretion	Participate in immune function of mucous membrane	Immunosuppressive effects	Job stress	Immunofluorescence staining and flow-cytometry analysis	Lee et al., 2010
4.	MicroRNA-29c	Expressed in the human prefrontal cortex	Involved in psychopathologies, such as schizophrenia and bipolar disorder and Alzheimer's, Huntington's and Parkinson's diseases	Indicate stress-induced functional neural alterations	Social stress task	TaqMan Low Density array/TaqMan real-time PCR assay	Vaisvaser et al., 2016
5.	miR-16	Acute psychological stress-responsive miRNAs	Play a role in the inhibition of inflammatory cytokine response	Indicate positive correlation with anxiety	Chronic academic stress	miRNA microarray/TaqMan® MicroRNA assays	Honda et al., 2013
6.	miR-146a and−212 expression	Responsive to inflammatory stimuli	Deficiency result in an excessive IL-6 and TNF-α production, myeloproliferative syndrome, chronic inflammation and a decrease in the number and quality of hematopoietic stem cells	Postpartum psychosis	Postpartum psychotic stress	TaqMan array human microRNA A Cards v2.0	Weigelt et al., 2013; Testa et al., 2017
7.	Relative telomere length	Repetitive DNA sequences present at the ends of eukaryotic chromosomes that undergoes attrition after every somatic cell division	Shorter telomeres are indicative of accelerated aging	Fear disorders including generalized anxiety disorder (GAD), panic disorder, agoraphobia, and social and other phobia	High phobic anxiety in women	Real-time polymerase chain reaction	Okereke et al., 2012
8.	Sigma-1 receptor	An endoplasmic reticulum chaperone involved in regulation of bioenergetics, free radical generation, oxidative stress, unfolded protein response, cytokine signaling, morphogenesis of neuronal cells	Its ligands exhibit antidepressant-like and neuroprotective actions	Mental disorders	Psychological stress	Single-cell reverse transcription-polymerase chain reaction (scRT-PCR) and immunofluorescence staining	Hayashi, 2015; Zhang K. et al., 2017
9.	Biopyrrins (bilirubin oxidative metabolites)	Biosynthesized from heme	Considered as harmful and useless substance	Associated with the risk of bilirubin encephalopathy and neuronal injury	Psychological stress	ELISA	Miyaoka et al., 2005
10.	Glycated hemoglobin (HbA1C)	HbA1c is considered as a possible substitute to fasting blood glucose for diagnosis of diabetes.	Independent risk factor for coronary heart disease and stroke	Anxiety, irritability, mood swings, insomnia, depression, and a sense of failure	Physical and emotional exhaustion mediated stress	Hexokinase assay and turbidimetric immunoinhibition methods by automatic analyzer	Sherwani et al., 2016; Deneva et al., 2019
11.	Cardiac troponin I	Considered as gold-standard biomarker for detecting acute myocardial necrosis and acute myocardial infarction	Cardiac damage during HS recovery	Multi-organ failure	Heat stroke stress	Handheld iSTAT clinical analyzer	Quinn et al., 2014; Park et al., 2017
12.	Osteopontin	A phosphoglycoprotein marker of hypoxic conditions	Involved in biomineralization, immune regulation and inflammation	Acute mountain sickness, high-altitude cerebral edema, high-altitude pulmonary edema	High altitude stress	ELISA	Basnyat, 2018; Tang X. G. et al., 2018