Comparative study of autonomic nervous system activity in malnourished and normal children in India

Information on the relationship between autonomic functions and malnutrition in children is scant. In the present study, autonomic function tests were conducted in 30 normal subjects and 30 malnourished children aged between 5 and 10 years. The tests performed included tests for parasympathetic functions (resting heart rate, standing-to-lying ratio, lying-to-standing ratio and Valsalva ratio) and tests to assess sympathetic function (hand grip test, galvanic skin resistance). The malnourished children had significantly lower mean weights-for-age (-2.6 Z vs -1.5 Z; p = 0.001), heights-for-age (-2.5 Z vs -1.5 Z; p = 0.001) and weights-for-height (-1.6 Z vs -0.8 Z; p = 0.001). Parasympathetic function tests evaluated were significantly affected in malnourished children. Resting heart rate was significantly higher in the malnourished group (90.6 vs 82.5/min; p = 0.001). The other parasympathetic function tests had significantly lower mean values than in the control group, namely, standing-to-lying ratio (1.25 vs 1.32; p = 0.026), lying-to-standing ratio (1.23 vs 1.29; p = 0.021) and Valsalva ratio (1.26 vs 1.28; p = 0.037). Of the sympathetic function tests conducted, there were no differences between the two groups for hand grip test but galvanic skin resistance was significantly higher in the malnourished subjects (190.1 vs 149.73; p = 0.001). It is concluded that autonomic nervous system function is significantly compromised in malnourished children.