To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
The aim of this study was to analyse whether changes in physical activity and body fatness are related to modifications in cardiovascular risk factors among adolescents.
Material and methods
A sample of 89 healthy adolescents was recruited for this study. We assessed habitual physical activity, body fat percentage, arterial thickness, blood sample, and biological maturation. Multivariate models were used to analyse the relationships between independent and dependent variables.
Physical activity (mean difference: 429.4 steps [95% confidence interval=−427 to 1286]) and body fatness (mean difference: −0.7% [95% confidence interval=−1.6–0.2]) remained stable during the study period. Independent of changes in physical activity, for each percentage increase in body fatness, femoral intima-media thickness increased by 0.007 mm (β=0.007 [95% confidence interval=0.001–0.013]). Longitudinal relationships were found for high-density lipoprotein-cholesterol (β=−0.477 mg/dl [95% confidence interval=−0.805 to −0.149]) and triacylglycerol (β=2.329 mg/dl [95% confidence interval=0.275–4.384]).
Changes in body fatness are more important than the amount of physical activity on cardiovascular and metabolic risks.
The objective of this study was to verify possible associations between heart rate variability indices and physical activity, body composition, and metabolic and cardiovascular parameters in individuals with type 1 diabetes.
A total of 39 young patients with type 1 diabetes were included. Body composition, physical activity, cardiovascular parameters, and metabolic parameters were assessed. For the heart rate variability analysis, heart rate was recorded beat-by-beat using a Polar S810i heart rate monitor for 30 minutes, with the volunteers in the supine position; subsequently, the following indices were considered: standard deviation of all normal RR intervals; root-mean square of differences between adjacent normal RR intervals in a time interval; percentage of adjacent RR intervals with a difference of duration >50 ms; high frequency component in milliseconds squared; high frequency component in normalised units; standard deviation of the instantaneous variability beat-to-beat; and standard deviation of the long-term variability. The association between the heart rate variability indices and independent variables was verified through linear regression in unadjusted and adjusted models (considering gender and age). The statistical significance was set at 5% and the confidence interval at 95%.
High values of at-rest heart rate were associated with reduced parasympathetic activity and global heart rate variability, and higher values of waist-to-hip ratio were related to lower parasympathetic activity, independent of age or gender.
For young patients with type 1 diabetes, increases in at-rest heart rate values are associated with reduced parasympathetic activity and global heart rate variability, whereas higher waist-to-hip ratio values are related to lower parasympathetic activity, both independent of age and gender.
Autonomic diabetic neuropathy is one of the most common complications of type 1 diabetes mellitus, and studies using heart rate variability to investigate these individuals have shown inconclusive results regarding autonomic nervous system activation.
To investigate the dynamics of heart rate in young subjects with type 1 diabetes mellitus through nonlinear and linear methods of heart rate variability.
We evaluated 20 subjects with type 1 diabetes mellitus and 23 healthy control subjects. We obtained the following nonlinear indices from the recurrence plot: recurrence rate (REC), determinism (DET), and Shanon entropy (ES), and we analysed indices in the frequency (LF and HF in ms2 and normalised units – nu – and LF/HF ratio) and time domains (SDNN and RMSSD), through analysis of 1000 R–R intervals, captured by a heart rate monitor.
There were reduced values (p<0.05) for individuals with type 1 diabetes mellitus compared with healthy subjects in the following indices: DET, REC, ES, RMSSD, SDNN, LF (ms2), and HF (ms2). In relation to the recurrence plot, subjects with type 1 diabetes mellitus demonstrated lower recurrence and greater variation in their plot, inter-group and intra-group, respectively.
Young subjects with type 1 diabetes mellitus have autonomic nervous system behaviour that tends to randomness compared with healthy young subjects. Moreover, this behaviour is related to reduced sympathetic and parasympathetic activity of the autonomic nervous system.
Email your librarian or administrator to recommend adding this to your organisation's collection.