PURPOSE: There is a deficit on autonomic nervous system regulation in individuals with Down syndrome (DS). However, the cardiac autonomic modulation during exercise in older adults with intellectual disability (ID) without DS is not enough described.
AIM: To evaluate and compare the heart rate variability (HRV) during the six-minutes walk test (6MWT) in older adults with and without ID.
METHODS: Seventeen participants with low-moderate ID non DS and 25 participants without ID were recruited. The HRV was assessed by R-R intervals on rest (10 minutes before the test), during the 6MWT and on recovery (10 minutes after the test), in orthostatic position by a Polar RS800X heart rate monitor. The symbolic analysis was used to evaluate nonlinear HRV components, and 0V% and 2UV% variations were considered as sympathetic and vagal modulation parameters, respectively. Two-way Anova was used to compare HRV parameters between the groups on rest, 6MWT and recovery.
RESULTS: Only the group without ID showed a significant increase of 0V% values (p=0.003), and a decreased 2UV% (p=0.003), as expected. Both groups showed a significant reduction in RRi mean (p=0.006). Distance walk on 6MWT was significant higher in the group without ID (536 m vs. 452 m (p=0.001)
CONCLUSION: participants with ID did not present cardiac autonomic modulation responses during the exercise, and show a worse performance in 6MWT. Thus, future studies are needed to elucidate the autonomic cardiac control during exercise in seniors with ID, and assist on prescription of appropriate intervention for this population.
Funding sources: MINECO (DEP2017-86862-C2-1-R); Generalitat de Catalunya. Departament d’Empresa i Coneixement (2019 FI_B 00893); Ministerio de Ciência e Tecnologia de Brasil (PDSE/CAPES 88881.189815/2018-01).
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| Table 1: Heart rate variability on older adults with and without ID | |
| Variables | Adults without ID (n = 25) | Adults with ID (n = 17) | |
| Mean (SD) | Mean (SD) | p |
| Linear Parameters | Rest | | 6MWT | | Recovery | Rest | 6MWT | Recovery | |
| Mean iRR (ms) * | 824 (168) | | 755 (167) | | 842 (167) | 849 (129) | 570 (80) | 790 (122) | .006 |
| Variance (ms²) | 778 (852) | | 721 (890) | | 810 (872) | 824 (849) | 887 (794) | 829 (737) | .052 |
| Non-Linear Parameters | | | | | | | | | |
| 0V% ** | 26 (16) | | 33 (16) | | 46 (14) | 33 (11) | 30 (15) | 32 (11) | .003 |
| 2UV% ** | 22 (12) | | 17 (8) | | 8 (6) | 13 (8) | 20 (11) | 14 (9) | .003 |
Note: values are means (Standard Deviation).
Abbreviations: ID (intellectual disability); 6MWT (six-minutes walk test); iRR (R-R intervals).
Statistically significant values are showed in bold (p ≤ .05).
* Significant difference (p ≤ .05) between rest and 6MWT for all groups.
** Significant difference (p ≤ .05) between rest and 6MWT w/ID group. |
