Abstract : After food ingestion, peptides are released in GIT, which cause local vasodilatation. Therefore, after meals, redistribution of blood occurs b e c a u s e o f s h i f t i n g o f l a r g e a m o u n t s o f b l o o d i n t o G I T . I n n o r m a l individuals, this is well compensated and does not lead to post-prandial hypotension. The mechanism of post-prandial hypotension is well known. We hypothesized that there may be a decrease in parasympathetic activity (tone) after meals to compensate for the change in blood distribution. We carried out the study to find out the changes in the autonomic tone before and after meals (lunch) in normal individuals, using Heart Rate Variability ( H R V ) . F r o m t h e s e r i e s o f R R i n t e r v a l s m a r k e d , t h e t i m e d o m a i n a n d f r e q u e n c y d o m a i n m e a s u r e s o f H R V w e r e o b t a i n e d u s i n g N e v r o k a r d software (version 6.4). Continuous ECG was recorded in 15 healthy adult subjects (mean age 29.06 ± 6.2; 13 males and 2 females). The ECG was r e c o r d e d i n p r e -p r a n d i a l a n d p o s t -p r a n d i a l s t a t e f o r a p e r i o d o f f i v e minutes each as follows: (1) just before the subjects had lunch, (2) 15 minutes after lunch, (3) 1 hour after lunch, and (4) 2 hours after lunch. T i m e d o m a i n a n d f r e q u e n c y d o m a i n m e a s u r e s o f H R V w e r e c o m p a r e d between pre-prandial state and rest of post-prandial states. The autonomic t o n e p a r a m e t e r s d i d n o t s h o w a s i g n i f i c a n t c h a n g e b e t w e e n t h e p r ep r a n d i a l s t a t e a n d t h e i m m e d i a t e p o s t -p r a n d i a l s t a t e . [ R a n g e , i . e . , t h e difference between the maximum and minimum RR intervals (406 ± 161.14 v s . 4 1 6 . 6 6 ± 1 2 5 ) , s t a n d a r d - Synopsis : Ambarish et al studied the changes in autonomic activity (tone) using heart rate variability (HRV) after feeding. Parasympathetic and sympathetic tone was studied in 15 healthy adult subjects before and after lunch. No significant change was seen in both when the autonomic tone parameters were compared. But the authors propose that HRV can be used to detect autonomic neuropathy in diabetics at a very early stage, by c o m p a r i n g p r e -p r a n d i a l a n d p o s t p r a n d i a l H R V
