. Author manuscript; available in PMC: 2017 Aug 1.

Published in final edited form as: Brain Behav Immun. 2016 Jan 14;56:221–229. doi: 10.1016/j.bbi.2016.01.014

Table 1.

Description of Each Physiological System Contributing to the Allostatic Load Index

Physiological Systems	Biomarkers
1. Sympathetic system	Based on urinary epinephrine and norepinephrine
2. Parasympathetic system	Based on heart rate variability measures, including the standard deviation of heartbeat-to- heartbeat intervals (SDRR), the root mean square of successive differences (RMSSD), and low- frequency and high-frequency heart rate variability
3. Hypothalamic–pituitary– adrenal (HPA) axis	Based on urinary cortisol and serum dehydroepiandrosterone sulfate (DHEA-S)
4. Inflammation	Based on fibrinogen, plasma C-reactive protein (CRP), serum interleukin 6 (IL-6), e-Selectin, and the intercellular adhesion molecule-1 (ICAM-1)
5. Cardiovascular system	Based on resting systolic blood pressure, resting heart rate, and pulse pressure
6. Metabolic system—glucose	Based on hemoglobin A1c (HbA1c), fasting glucose, and insulin resistance quantified through the homeostatic model assessment (HOMA-IR)
7. Metabolic system—lipids	Based on body-mass index (BMI), waist-hip ratio (WHR), triglycerides, high density lipoprotein (HDL) cholesterol, and low density lipoprotein (LDL) cholesterol