Publication: Heart rate variability: Response to graded head up tilt in healthy men
| creativeworkseries.issn | 1812-2027 | |
| dc.contributor.author | Sharma, P | |
| dc.contributor.author | Paudel, BH | |
| dc.contributor.author | Singh, PN | |
| dc.contributor.author | Limbu, P | |
| dc.date.accessioned | 2025-08-06T07:21:31Z | |
| dc.date.available | 2025-08-06T07:21:31Z | |
| dc.date.issued | 2009 | |
| dc.description | Sharma P 1, Paudel BH2 , Singh PN 3 , Limbu P4 1 Lecturer, Department of Physiology, Kathmandu Medical College, Kathmandu, Nepal, 2Additional Professor, 3Professor,4 PG student, Department of Physiology, BP Koirala Institute of Health Sciences, Dharan, Nepal | |
| dc.description.abstract | Abstract Background: Heart rate variability is actually a misnomer for R to R variability in cardiac cycle. Variation in successive cycle length is called the heart rate variability (HRV). Head-up tilt is a model of studying cardiovascular haemodynamics, which reflects in heart rate variability (HRV). Objectives: To study the effect of 10° and 70° head-up tilt on HRV. Materials and methods: The study was done in the Department of Physiology using graded head up tilt (passive orthostatism). HRV measurement was done at 10° and 70° tilt and compared with supine using standardised methods on 30 consenting healthy males (age 25.37±3.89 years). The HRV variables across postures were compared by ANOVA and Bonferroni test. Results: The heart rate increased at 70° compared to 10° and supine (70.48±8.17 Vs 70.22±8.67 and 88.51±12.84 bpm, p<0.001). The 70° tilt decreased vagal HRV indicators compared to 10° and supine: SDNN (31.13±8.12 Vs 38.07±11.29 and 38.13±10.89 ms, p<0.05), RMSSD (20.06 ±8.47 Vs 34.23±14.22 and 36.16±12.22 ms, p<0.001), NN50 count (13.03±20.58 Vs 45.07±44.44 and 55.27±44.10, p<0.01), pNN50 (3.28±6.08 Vs 14.06±15.65 and 16.65±14.23, p<0.01), HF power (197.20±143.76 Vs 218.17±155.85 and 216.87±150.98 Hz, p<0.05), HFnu unit (24.28±14.16 Vs 45.48±16.34 and 47.67±19.89, p<0.001). The 70° tilt increased LF power% (197.20±143.76 Vs 218.17±155.85 and 216.87±150.98, p<0.001). LFnu unit (75.72±14.76 Vs 54.52±16.34 and 52.32±19.89, p<0.001), LF: HF (4.96±4.08 Vs 1.53±1.138 and 1.69±1.67, p<0.001) compared to 10° and supine. Conclusion: At 70° tilt, HRV measures, reflecting vagal contribution to cardiac-cycle length, decreased with reciprocal increase in sympathetic activity compared to 10° or supine leading to increase in sympathetic predominance. A 10° tilt, which is almost equivalent to lying down with pillow, did not change HRV from supine. Key words: Cardiac cycle, cardiovascular haemodynamics, head-up-tilt, heart rate variability, sympathetic activity, parasympathetic activity | |
| dc.identifier.uri | https://hdl.handle.net/20.500.14572/1315 | |
| dc.language.iso | en_US | |
| dc.publisher | Kathmandu University | |
| dc.title | Heart rate variability: Response to graded head up tilt in healthy men | |
| dc.type | Article | |
| dspace.entity.type | Publication | |
| local.article.type | Original Article | |
| oaire.citation.endPage | 60 | |
| oaire.citation.startPage | 55 | |
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