Introduction: The effect of clothing on the recording of blood pressure in a normotensive and hypertensive population remains essential to diagnosing and managing. Methods: This is a cross-sectional study to measure blood pressure using a validated oscillometric sphygmomanometer in two populations. The records were made over the thicker sleeve arm and non-sleeved arm (either on bare arm or indicating the removal of the outermost garment). Clothing was categorized according to how patients attended the outpatient clinic based on the real world. Results: A total of 75 patients were included with a diagnosis of hypertension whose mean age was 67.1 years (SD ± 16.3). The group of normotension included 63 patients whose mean age was 21.1 years (SD ± 2.2). There was not variability related to technique or inherent to the condition of the subject on the first and second measurements of blood pressure. In the comparative analysis, the group with normotension did not report a significant difference in systolic or diastolic blood pressure due to the effect of clothing during the first or second measurement (p > 0.05). In the group with hypertension, a significant difference was observed in the first measurement, between the group over-the-sleeve and non-sleeved arm (systolic blood pressure, p: 0.021 and diastolic, p: 0.001). However, when the variable order of measurement was analyzed by randomizing the initial registry with or without clothing was not found a statistical difference. Conclusion: Clothing does not a significant difference in the measure of blood pressure in a normotensive or hypertensive population.

The use of oscillometric sphygmomanometers for the recording of ambulatory (home and office monitoring) blood pressure has been extended in the last guidelines, being a recommendation included for the diagnosis of hypertension by the European Society of Hypertension endorsed by the International Society of Hypertension and the European Renal Association in its latest update [1, 2]. This method is suitable whenever errors related to technique are reduced. One recommendation for recording blood pressure according to the eighth report of the Joint National Committee [3], the American Heart Association [4], and the European Society of Hypertension [1] is to be performed with the bare arm; however, there are reports with not significant evidence for this daily practice. Liebl et al. [8] reported not differences in normotensive and hypertensive populations related to the effect of wearing clothes. Moreover, it has been described that clothing is left underneath the cuff in clinical practice. In routine medical practice, a correct recording technique is not a frequent practice since only 51% of doctors and nurses develop the correction of the position of the arm at the level of the heart, 32% refer to the fact that there is no need of supporting the arm, 76% did not deflate 2–3 mm Hg/s and more than half of the doctors rounding off reading to the nearest 5 mm Hg [5]. Instead, the assessment of risk or benefit for a patient needs an accurate recording of blood pressure since a reduction of 2 mm Hg in a hypertensive patient is associated with 10% less mortality from stroke and 7% less than ischemic heart disease [6]. There are other variables influencing the precision of blood pressure measurement, in addition to technique, such as the inherent variability and the effect of a white coat because of the tendency of blood pressure to increase in the presence of a physician [7]. Concerning the effect of clothing on the technique to record blood pressure, some studies have not reported differences in the normotensive or hypertensive population [8‒11]. A study in patients over 65 years, reported significantly increased blood pressure if using a garment with a diameter greater than 0.5 mm [12]; however, other studies are not consistent with these findings, hence, the evidence is inconclusive. This study aims to analyze this practice, comparing the differences in blood pressure of a normotensive and hypertensive population between bare and clothed arms. In the case of clothing, it was included the garment worn regularly by the population. The final interpretation is important to improve the proper measure of ambulatory recording of blood pressure.

This is a cross-sectional study. The normotensive patients were medical students from Medical School. The hypertensive population was included during their ambulatory control from the Nephrology service of the Hospital Guillermo Almenara. All patients signed the informed consent. The inclusion criteria were over the age of 18 years, blood pressure <140/90 mm Hg in the normotensive population, and blood pressure ≥140/90 mm Hg in the hypertensive population, according to the diagnostic criteria of the 2023 guideline of the European Society of Hypertension endorsed by the International Society of Hypertension [1]. Exclusion criteria were if the participant wore only a thinner piece of clothing (categorized as less thickness) that could not be removed for the comparative record non-sleeved. The study was conducted during the winter season, so the majority of the population wore a non-thin garment. The period of data collection was of 3 months. Other exclusion criteria were strenuous physical activity half an hour before, drinking coffee, psycho-stimulants, smoking, functional upper limb immobility, a history of hypertension in the normotensive population, and a history of arteriovenous fistula in the hypertensive population. The study was approved by the Local Ethics Committee (note N◦305 CIEI-OIyD-GRPA-ESSALUD).

An oscillometric automatic blood pressure monitor was used (A&D medical®, model UA-767F) with an adjustable shaft between 22 and 42 cm, validated by the European Society of High Blood Pressure. Blood pressure was recorded 4 times in each participant, twice with the arm covered in thicker clothing, and twice with the bare or thinner arm (removing the outermost garment). The clothing was categorized: (1) less thickness (polo or shirt or T-shirt), (2) intermediate thickness (thin jacket or suit jacket or sweater), and (3) thicker (cashmere jacket or thick jacket or jacket with lining or leather jacket or windbreaker or coat or sweatshirt or jogging suit). The categorization of the clothes was as patients come to the outpatient clinic to extrapolate the results to real-world practice.

The resting time before the first measurement was 5 min and the time between measurements was at least 2 min. The recording was performed in a sitting position with the elbow and forearm supported on an evaluation table in the right arm, the legs not crossed and the patient without speaking and without isometric effort during the recording. If the blood pressure monitor showed an error during registration (signal of error from the device), it was indicated to raise the right arm and contract and relax the hand to avoid the phenomenon of reactive hyperemia [4, 7, 13].

To rule out a possible bias of an initial registry of higher blood pressure in the office, considered in a previous report [14, 15], the order of measurement was randomized into two groups for subsequent analysis. Hence, it was changed the order of measurement between over-the-sleeve and the non-sleeved arm.

The statistical analysis to determine differences in blood pressure required a sample size of 63 participants for each group. It was estimated based on a difference of 5 mm Hg and a standard deviation of 10 mm Hg, alpha = 0.05, and a statistical power of 80% [8]. The differences in blood pressure measurements because of the type of clothing used the Kruskal-Wallis test. The statistical evaluation of clothing between over-the-sleeve and non-sleeved arm groups used the Wilcoxon test for paired samples. Age, sex, obesity according to body mass index (BMI), smoking history (if smoked ≥1 cigarette in the last 6 months) were analyzed to determine association. The confidence interval was 95% with a statistical significance of p ≤ 0.05. Statistical software SPSS 25.0 was used.

Seventy-five patients with a diagnosis of hypertension and 63 patients with normotension were included. The mean age was 21.1 years (SD ± 2.2) in the normotension group and 67.1 years (SD ± 16.3) in the hypertension group. The data on sex, BMI, smoking, and type of clothing are shown in Table 1. The predominant type of clothing was of intermediate thickness and thickest. Neither normotensive nor hypertensive groups had not variability in the measure of the blood pressure. The differences between the first and second measurement over-sleeve arm in systolic blood pressure record a median 5, SD 13 mm Hg; diastolic blood pressure, median 1, SD 8 mm Hg; in non-sleeved arm, systolic blood pressure, median 2, SD 11 mm Hg; diastolic blood pressure, median 0, SD 7 mm Hg so there were not related factors associated to technique or inherent to the condition of the subject.

Table 1.

Descriptive characteristics of subjects with normal blood pressure and hypertension

Total sample: 138Normotensive (63)Hypertensive (75)
Age, years (SD) 21.1±2.2 67.1±16.3 
Male, % 52.4 (33) 53.3 (40) 
Body mass index, kg/m2 (SD) 23.4±2.1 26.0±4.7 
Smoking, % 27.0 (17) 18.7 (14) 
Type of clothing, % 
 *Less thickness 9.5 (6) 5.3 (4) 
 **Intermediate thickness 42.9 (27) 50.7 (38) 
 ***Thickest 47.6 (30) 44 (33) 
Total sample: 138Normotensive (63)Hypertensive (75)
Age, years (SD) 21.1±2.2 67.1±16.3 
Male, % 52.4 (33) 53.3 (40) 
Body mass index, kg/m2 (SD) 23.4±2.1 26.0±4.7 
Smoking, % 27.0 (17) 18.7 (14) 
Type of clothing, % 
 *Less thickness 9.5 (6) 5.3 (4) 
 **Intermediate thickness 42.9 (27) 50.7 (38) 
 ***Thickest 47.6 (30) 44 (33) 

*Less thickness (polo or shirt or T-shirt).

**Intermediate thickness (thin jacket or suit jacket or sweater).

***Thicker (cashmere jacket or thick jacket or jacket with lining or leather jacket or windbreaker or coat or sweatshirt or jogging suit).

The comparative record of mean arterial pressure in the normotensive group is shown in Table 2 and Figure 1. The records of the first and second measurements in the group over the sleeve considering the type of clothing did not have a significant difference in blood pressure values (systolic pressure, p = 0.958 in the first measurement, p = 0.977 in the second measurement).

Table 2.

Blood pressure measure over-the-sleeve and non-sleeved arm groups with normotension (n: 63)

Systolic blood pressure, mm Hgp value*Diastolic blood pressure, mm Hgp value*
Type of clothing (1st measurement) Median, SD 0.958 Median, SD 0.457 
 Less thickness 111±6  66±8  
 Intermediate thickness 110±15  70±10  
 Thickest 109±11  68±9  
Type of clothing (2nd measurement) 
 Less thickness 110±12 0.977 67±10 0.640 
 Intermediate thickness 110±13  70±9  
 Thickest 110±12  70±8  
Non-sleeved (1st measurement) 110±12  69±10  
Non-sleeved (2nd measurement) 108±12  68±9  
Systolic blood pressure, mm Hgp value*Diastolic blood pressure, mm Hgp value*
Type of clothing (1st measurement) Median, SD 0.958 Median, SD 0.457 
 Less thickness 111±6  66±8  
 Intermediate thickness 110±15  70±10  
 Thickest 109±11  68±9  
Type of clothing (2nd measurement) 
 Less thickness 110±12 0.977 67±10 0.640 
 Intermediate thickness 110±13  70±9  
 Thickest 110±12  70±8  
Non-sleeved (1st measurement) 110±12  69±10  
Non-sleeved (2nd measurement) 108±12  68±9  

*p: Kruskal-Wallis.

Fig. 1.

Axis X: comparative recording of blood pressure in the normotensive over-the-sleeved and non-sleeved arm groups in the first and second measurements. Axis Y: blood pressure (mm Hg). SBP, systolic blood pressure; DBP, diastolic blood pressure.

Fig. 1.

Axis X: comparative recording of blood pressure in the normotensive over-the-sleeved and non-sleeved arm groups in the first and second measurements. Axis Y: blood pressure (mm Hg). SBP, systolic blood pressure; DBP, diastolic blood pressure.

Close modal

The analysis of the effect of clothing on the recording of blood pressure between over-the-sleeve and non-sleeved arm groups was performed in the group with normotension. The statistical analysis used was the Wilcoxon test for paired samples. There was not statistically significant difference in systolic blood pressure either in the first or the second measurement (first measurement: p = 0.274 and second measurement: p = 0.138). The diastolic blood pressure did not have a significant difference either (first measurement: p = 0.524 and second measurement: p = 0.068).

In the group with hypertension, the record of mean arterial pressure is shown in Table 3. There was no significant difference in terms of the record of blood pressure in the group with different types of clothing during the first or second measurement (p = 0.358 and p = 0.507, respectively, systolic pressure). Figure 2 shows the differences in this registry in patients with hypertension.

Table 3.

Blood pressure recording in the over-the-sleeve and non-sleeved arm groups with hypertension (n: 75)

Systolic blood pressure, mm Hgp value*Diastolic blood pressure, mm Hgp value*
Type of clothing (1st measurement) Median, SD 0.358 Median, SD 0.624 
 Less thickness 167±30  89±21  
 Intermediate thickness 168±24  84±16  
 Thickest 174±23  86±15  
Type of clothing (2nd measurement) 
 Less thickness 169±33 0.507 92±19 0.481 
 Intermediate thickness 162±22  82±17  
 Thickest 168±15  85±14  
Non-sleeved (1st measurement) 166±22  81±17  
Non-sleeved (2nd measurement) 164±22  81±16  
Systolic blood pressure, mm Hgp value*Diastolic blood pressure, mm Hgp value*
Type of clothing (1st measurement) Median, SD 0.358 Median, SD 0.624 
 Less thickness 167±30  89±21  
 Intermediate thickness 168±24  84±16  
 Thickest 174±23  86±15  
Type of clothing (2nd measurement) 
 Less thickness 169±33 0.507 92±19 0.481 
 Intermediate thickness 162±22  82±17  
 Thickest 168±15  85±14  
Non-sleeved (1st measurement) 166±22  81±17  
Non-sleeved (2nd measurement) 164±22  81±16  

*p: Kruskal-Wallis.

Fig. 2.

Axis X: comparative recording of blood pressure in the hypertensive over-the-sleeved and non-sleeved arm groups in the first and second measurements. Axis Y: blood pressure (mm Hg). SBP, systolic blood pressure; DBP, diastolic blood pressure.

Fig. 2.

Axis X: comparative recording of blood pressure in the hypertensive over-the-sleeved and non-sleeved arm groups in the first and second measurements. Axis Y: blood pressure (mm Hg). SBP, systolic blood pressure; DBP, diastolic blood pressure.

Close modal

The analysis of the effect of clothing on the recording of blood pressure between over-the-sleeve and non-sleeved arm groups was performed in the group with hypertension. The statistical analysis used was Wilcoxon test for paired samples. It was found a significant difference between these groups in systolic (p = 0.021) and diastolic pressure (p = 0.0004) during the first measurement. The mean systolic blood pressure over the sleeve was 171 ± 23 mm Hg and non-sleeved arm of 166 ± 23 mm Hg. No differences were found in the second measurement of systolic (p = 0.557), but there was significative difference in diastolic (p = 0.0002) blood pressure. However, it was considered as possibility an elevation of blood pressure record in the office during the initial measurement. Consequently, the order of measurement in the record was analyzed (over-the-sleeve or non-sleeved arm). If the significant difference is maintained and not associated with the order of measurement, it would be suggestive of the effect of clothing, but if it is not maintained, its attribution is possible to the increase of blood pressure initially in the office. This type of analysis randomized both groups. In the group with hypertension, the initial registration was done with clothing (53 patients), and then without clothing (22 patients). When the order was clothing/no clothing (clothing first), it was found a significant difference (systolic blood pressure, p = 0.003 and diastolic blood pressure, p = 0.00002), but not if the recording started without clothing (no clothing/clothing) (systolic blood pressure, p = 0.614 and diastolic blood pressure, p = 0.986), consequently, there was no persistent effect of clothing on blood pressure. The increase in blood pressure reported only during the first recording can be attributed to the expected increase in baseline blood pressure in the medical doctor’s office. Moreover, the difference in diastolic pressure during the first and second measure is not confirmed when the order of measuring is applied. Finally, the analysis of independent variables (smoking, sex, obesity) did not find a difference significant regarding to use or not of clothing between the groups of normotension and hypertension (online suppl. Table 1; for all online suppl. material, see https://doi.org/10.1159/000538164).

Technique errors in blood pressure recording and inadequate equipment can produce a measurement difference of up to 15 mm Hg [16]. Consequently, all measures that reduce this error should be emphasized. Our results did not demonstrate a difference in blood pressure measurement due to the effect of clothing. Before the analysis of paired samples, the over-sleeve group did not register a significant difference of at least 5 mm Hg in terms of the expected variability factor, nor the non-sleeved arm group. A previous report did not find a significant difference in non-sleeved arms during two records of systolic blood pressure with variability of blood pressure of 4.1 mm Hg nor in the over-sleeve group with a difference of 3.4 mm Hg [17]. Though it has been described that the variability of blood pressure occurs mainly in arterial hypertension, due to the increase in arterial stiffness associated with age and lower compliance [18], however, it was not significant in this report.

The analysis of paired samples, over-sleeve and non-sleeved arm groups, also found no differences. However, initially, there was a difference in analyzing the first measurement. This result could be influenced by the effect of the initial elevation of blood pressure in the office when the initial registration is done with clothing before the indication of its removal. When the order of registration was analyzed, these same-paired samples did not have significant differences independent of the order of measurement, so the difference was not sustained by the effect of clothing, but by the initial record of higher blood pressure in a random group. Consequently, this finding is consistent with the recommendations of the clinical guidelines of at least 2 blood pressure records since between 18% and 33% of patients classified as hypertension stage 1 or 2 in the initial record are reclassified to categories minor [15]. For this reason, ambulatory monitoring is becoming increasingly important for both diagnosis and treatment.

The methodology of this study was adjusted to the recording of blood pressure in the real world, where patients who come with thicker clothing, remove the outermost one. Similarly, patients are generally not left with the arm fully uncovered, but with the thinnest garment. The main strength of our study is the evidence of the non-difference effect of clothing on blood pressure measuring in hypertensive population when methodologically the order of measuring is introduced, hence, the presumed comparative difference reported in other studies, actually is a consequence of the initial elevation of blood pressure in the office. Finally, the use of oscillometric tensiometers is an increasingly widespread practice incorporated in the office. Therefore, the results have practical repercussions. Our limitation was the dichotomization of many groups from two different populations. It would be convenient to focus on hypertensive population, and explore an estimation of sample size based on a difference of 4 mm Hg.

Recently, Tal-Ben et al. [19] reported differences between sleeved and bare arms measurements based on “absolute values” and recommend measuring blood pressure on bare skin because the effect seems to be “unpredictable”; however, the same study did not find statistical significant differences between the sleeved and the bare arm measurements, despite the collected blood pressure were done simultaneously in the right and left arm, where we presume differences.

Is important a correct recording technique to proper ambulatory measures of blood pressure. In that regard, our study evidence there are no significant differences between the recording of blood pressure with or without clothing in a normotensive or hypertensive population. Moreover, this study opens future research to analyze the differences that could be found in the hypertensive population during the first registration because the increase in initial blood pressure is a finding we can see in the outpatient clinic and not by clothing effect.

Author Willian Cepeda Horna was not available to confirm co-authorship, but the corresponding author Dr Castillo Velarde affirms that Willian Cepeda Horna contributed to the paper, had the opportunity to review the final version to be published and guarantees Willian Cepeda Horna co-authorship status and the accuracy of the author contribution and conflict of interest statements.

The study was approved by the Local Ethics Committee of Hospital Guillermo Almenara (Note 305 CIEI-OIyD-GRPA-ESSALUD). Written informed consent was obtained from the patients for publication.

The authors have no conflicts of interest to declare.

The authors have no funding sources to declare.

Edwin Castillo Velarde: manuscript draft, analysis and interpretation of data, review of literature, and final version; Jorge Roca-Sánchez-Moreno, Alison Núñez Muñoz, Alessandra Guillen Rivera, Mary Hidalgo Babilonia, Jherson García Meneses, Lisseth Mamani Turpo, and Willian Cepeda Horna: acquisition of data, manuscript draft, and final version.

The data that support the findings of this study are openly available in repository figshare at https://doi.org/10.6084/m9.figshare.14369828.v1.

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