type 2 diabetes mellitus ( t2d ) is a metabolic disorder characterized by the inability of 
 insulin to properly perform its function , resulting in chronic hyperglycemia1 and it is also associated with endothelial 
 dysfunction2 , increase in sympathetic 
 tone3 and several cardiovascular 
 disorders , such as systemic arterial hypertension ( sah)4 and coronary artery disease ( cad)5 . the increase in the incidence of t2d is mainly the result of 
 genetic predisposition , dietary excess of foods rich in fat and sugar , obesity , sedentarism 
 and low levels of physical fitness6 , 7 .
the frequent practice of physical exercise helps to both prevent and treat t2d and its 
 complications8,9,10 .
the benefits of exercise 
 for diabetic individuals include better glycemic control11 , 12 , reduction of blood 
 pressure ( bp)13,14,15 and improvement of 
 cardiorespiratory tness12 , 16 all of which , are associated with cardiovascular events 
 and mortality17 .
the reduction of bp in 
 the post - exercise ( recovery ) period to values below those observed during pre - exercise 
 ( rest ) is called post - exercise hypotension ( peh)18 . this phenomenon can be observed both in normotensive19 and hypertensive individuals20 , 21 , and in the latter , a post - exercise bp reduction from 12 h22 , 23 
 to 24 h24 , 25 has also been observed .
the prescription of an appropriate amount of exercise is recommended for t2d patients , and 
 it should be based on intensities that are related to their aerobic and physical capacities . 
 to accomplish this ,
it is necessary to perform incremental tests for the evaluation of 
 functional ability , such as the anaerobic threshold ( at ) and maximum oxygen uptake 
 ( vo2max ) tests26,27,28 .
these tests are 
 currently used by studies investigating the prescription of aerobic exercise for bp control 
 in individuals with t2d14 , 15 . however ,
some studies14 , 15 have only analyzed bp for two hours post - exercise and have 
 not investigated whether the benefits extend over the following 24 hours , including sleep . 

it is known that t2d is associated with endothelial dysfunction2 , therefore , this pathology could attenuate the expected 
 benefits of acute aerobic exercise on bp3 . 

consequently , the objectives of this study were to verify and compare : 1 ) the effects of a 
 single aerobic exercise session on 24-hour bp responses and 2 ) the effects of aerobic 
 exercise intensity on 24-hour bp responses of individuals with t2d and prehypertension .
013/2008 ) , 10 
 participants aged between 45 and 70  years old were enrolled ( 3 men and 7 women ; table 1table 1.anthropometric characteristics and parameters of aerobic fitness during 
 incremental load test performed by individuals with t2d ( n=10)age ( years)55.8  7.7weight ( kg)79.4  14.0height ( cm)160.7  11.3bmi ( kgm)30.7  4.2abdominal circumference ( cm)102.1  13.7bodyfat ( % ) 29.2  9.9time with dm ( years)6.3  3.1fg ( mgdl)133.0  36.7awake sbp ( mmhg)130.6  1.6awake dbp ( mmhg)80.5  1.8hrmax ( bpm)150.3  23.5pmax ( watts)85.5  22.4[lac ] max ( mm)6.7  2.0vo2peak ( mlkgmin)20.2  4.1lt ( watts)49.5  23.5[lac ] lt ( mm)3.2  0.9vo2 at lt 
 ( mlkgmin)14.6  3.7bmi : body mass index ; fg : fasting glycemia ; sbp : systolic blood pressure ; dbp : 
 diastolic blood pressure ; vo2peak : peak consumption of oxygen ; pmax : the 
 highest power output ( watts ) obtained in the incremental test on a cycle ergometer ; 
 hrmax : maximum heart rate ; [ lac ] : blood lactate concentration ; lt : lactate 
 threshold ) after they signed an informed consent form before participation in the study . 

inclusion criteria were sedentary life style , a diagnosis of t2d for at least one year , 
 glycemic control through nutrition and/or medication ( e.g. sulfonylureas , metformin , 
 metformin+glibenclamide , glimepiride , pioglitazone chloridrate ) , no use of exogenous insulin 
 and no chronic complications , such as , diabetic foot , nephropathy , retinopathy , neuropathies 
 or cardiovascular diseases .
all participants were recruited from a public hospital at 
 taguatinga , and all had been previously assessed in standard tests conducted by 
 endocrinologists and cardiologists .
this meant that , at the time of recruitment , all 
 subjects with a positive history for any of the tests were eliminated from the study .
bmi : body mass index ; fg : fasting glycemia ; sbp : systolic blood pressure ; dbp : 
 diastolic blood pressure ; vo2peak : peak consumption of oxygen ; pmax : the 
 highest power output ( watts ) obtained in the incremental test on a cycle ergometer ; 
 hrmax : maximum heart rate ; [ lac ] : blood lactate concentration ; lt : lactate 
 threshold after anthropometric and resting electrocardiography ( ecg ) evaluations and familiarization 
 with the experimental procedures , the volunteers participated in three 
 cardiologist - supervised experimental sessions on different days : 1 ) maximal exercise ( max ) ; 
 2 ) moderate exercise ( mod ) ; and 3 ) a control session ( con ) with no exercise .
sessions 2 and 
 3 were performed on alternate days in a randomized order at the same time of day ( between 
 8:30 and 9:00 h ) , with a 48-hour interval between sessions .
two hours before the sessions 
 the participants ate a standardized breakfast of 315  kcal , containing 66% ( 51.6  g ) 
 carbohydrates , 6% ( 4.6  g ) of protein and 27% ( 9.5  g ) of fat .
before sessions the participants remained at rest for 20 minutes for bp ( dyna - mapa  
 cardios ) and hr ( polar s810i ) measurements , while capillary blood 
 samples were collected for [ lac ] determination ( ysi 2700  yellow springs  usa ) . during the 
 post - experimental period , the participants remained seated for a period of 60 minutes , while 
 the measurements of bp and hr , and blood sample collections were taken every 15 minutes . 

after that , the participants were allowed 20 minutes for personal hygiene before the 
 placement of an ambulatory blood pressure monitor ( dyna - mapa  cardios ) , which 
 measured their bp for the 24 hours subsequent to their exercise or control sessions . 

ambulatory blood pressure monitor ( abpm ) was carried out every 30  min after the sessions 
 until 2300 h , after that time , hourly , until 0700 h , as per the iv guidelines for ambulatory 
 blood pressure monitoring28 .
abpm data 
 were considered in the analysis when 90% of the measurements were valid .
participants were 
 instructed to perform their habitual daily activities and to keep the non - dominant upper 
 limb ( where the measuring cuff was placed ) in a relaxed position while the bp was being 
 measured28 .
max consisted of a graded cardiopulmonary exercise stress test ( lode excalibur sports , 
 netherlands ) .
vo2peak was determined by breath - by - breath analysis of expiratory 
 gases during exercise as previously described29 .
the gas analyzer was calibrated with a 3-l syringe ( flow 
 calibration ) and a standard mixture of gas containing 4.9% co2 and 17% 
 o2 ( gas calibration ) .
an incremental load test was initiated with one minute of 
 warm - up at a zero watt ( w ) load , followed by increments of 15  w every 3 minutes , consisting 
 of continuous cycling at a constant cadence ( 60 revolutions per minute ) until voluntary 
 exhaustion of the participant . at rest and during the nal 10 sec of each stage of the max , 
 blood samples were collected for blood lactate analysis ( [ lac ] ) using a ysi 2700 
 biochemistry analyzer ( ysi inc , yellow springs , oh , usa ) . in addition , bp was measured by 
 the auscultatory method , using a mercury column sphygmomanometer ( tycos instrumentos 
 hospitalares , so paulo , brazil ) .
heart rate ( hr ) was monitored using a polar 
 s810i heart - rate monitor ( polar electro oy , kempele , finland ) , rate of perceived exertion 
 ( rpe ) was rated on the 20-point borg scale30 , and ventilatory variables were also recorded ( metalyzer 3b system ; 
 cortex , leipzig , germany ) .
max allowed identication of the lactate threshold ( lt ) and 
 measurement of the vo2peak .
the lt was identified through visual inspection of 
 the lactate curve ; the lt was considered the intensity at which a loss of linearity and an 
 abrupt and exponential increase in the lactate curve occurred31 , 32 .
the mod session consisted of 20 minutes of cycle ergometer exercise ( lode excalibur sports , 
 netherlands ) at a constant load corresponding to 90% of the lt ( 90%lt ) .
the con was a 
 20-minute session of seated rest . at 10 and 20  min during mod and con ,
bp , hr , [ lac ] , rpe 
 and ventilatory variables were measured .
data are presented as mean (  ) standard deviation and as absolute variations ( delta 
 absolute ) , as indicated for each analysis . after assessing the normality and homogeneity 
 of the data using the shapiro - wilk test and levene s test , respectively , between- and 
 within - groups
comparisons were performed using split - plot anova ( mixed anova ) with 
 scheffe s post hoc test .
when any of the dependent variables did not show sphericity in 
 the mauchly s test , the epsilon of greenhouse - geisser was used to analyze the f statistic . 

the level of significance was chosen as 5% ( p0.05 ) and all analyses were carried out 
 using the statistical package for the social sciences ( spss ) 15.0 .
data are presented as mean (  ) standard deviation and as absolute variations ( delta 
 absolute ) , as indicated for each analysis . after assessing the normality and homogeneity 
 of the data using the shapiro - wilk test and levene s test , respectively , between- and 
 within - groups
comparisons were performed using split - plot anova ( mixed anova ) with 
 scheffe s post hoc test .
when any of the dependent variables did not show sphericity in 
 the mauchly s test , the epsilon of greenhouse - geisser was used to analyze the f statistic . 

the level of significance was chosen as 5% ( p0.05 ) and all analyses were carried out 
 using the statistical package for the social sciences ( spss ) 15.0 .
the subjects were 10 persons , 3 men and 7 women with t2d , according to the fasting 
 glycemia1 , and prehypertension33 .
the participants were overweight to 
 obese34 and had low physical 
 fitness35 ( table 1 ) . the aerobic fitness , metabolic and hemodynamic 
 parameters obtained during all the sessions ( max , mod and con ) are presented in tables 1 and 
 2table 2.mean ( dp ) results of metabolic and hemodynamic parameters , rate of perceived 
 exertion and the duration of sessionsmaxmodcon[lac ] ( mm)6.7  2.0 3.8  1.22.5  0.8*vo2 ( mlkg  min1)20.2  4.114.0  3.04.2  0.3*% vo2peak100  0.0 69.4  8.1-watts85.5  22.444.6  21.2-hr ( bpm)150.3  23.5114.5  25.173.2  9.1*sbp ( mmhg)197.8  14.0147.0  15.5125.2  13.3*dbp ( mmhg)89.7  6.284.5  7.278.8  7.3rpe ( score)19  1.3 11  2.3-duration ( min)18.7  4.520.0  0.020.0  0.0[lac ] : concentration of blood lactate ; peak vo2 : highest value of oxygen 
 consumption ; % vo2 peak : percentage of peak oxygen consumption reached ; hr : 
 heart rate ; sbp : systolic blood pressure ; dbp : diastolic blood pressure ; rpe : rate of 
 perceived exertion . * p0.05 in relation to sessions max and mod ;  
 p0.05 in relation to mod . no subject exhibited a hypertensive response , defined as sbp 210 mmhg and 
 dbp  105 mmhg36 , to the graded exercise 
 test .
[ lac ] : concentration of blood lactate ; peak vo2 : highest value of oxygen 
 consumption ; % vo2 peak : percentage of peak oxygen consumption reached ; hr : 
 heart rate ; sbp : systolic blood pressure ; dbp : diastolic blood pressure ; rpe : rate of 
 perceived exertion . * p0.05 in relation to sessions max and mod ;  
 p0.05 in relation to mod table 3table 3.mean results ( sd ) of 24-h systolic blood pressure ( sbp ) , diastolic ( dbp ) and 
 mean arterial pressure ( map ) after the max , mod and con sessionsparametersmaxmodconsbp ( mmhg)resting132.1 11.4129.0  10.5130.8  8.424 h124.3  7.4 * 127.7  7.1132.8  10.6waking126.6  8.0 * 129.7  7.1135.8  10.9sleeping116.8  9.8 #121.5  12.0124.6  11.6dbp ( mmhg)resting81.6  6.780.3  8.879.7  10.124 h76.3  4.5 * 78.9  3.782.2  5.0waking77.9  5.1 * 80.4 
3.883.9  5.2sleeping70.8  4.7*#73.6  7.477.1  5.4map ( mmhg)resting102.6  8.2101.0  8.4101.3  9.324 h95.4  4.6 * 98.2  3.4102.5  6.9waking97.3  5.5 * 100.2  3.5104.8  7.4sleeping89.2  5.2*#91.6  6.9 95.8  6.3*p<0.05 in relation to control session ; p<0.05 in relation to pre - exercise 
 rest of the same session ; # in relation to waking period of the same session ;  in 
 relation to 24  h of the same session presents the mean values of sbp , dbp and map at rest and during ambulatory 
 measurement of blood pressure ( abpm ) after the experimental sessions and control .
the 
 post - max exercise sbp , dbp and map over 24 h , in the waking and sleeping ( dbp and map ) 
 period were significantly different from the respective values obtained after the con 
 session ( p<0.05 ) .
* p<0.05 in relation to control session ; p<0.05 in relation to pre - exercise 
 rest of the same session ; # in relation to waking period of the same session ;  in 
 relation to 24  h of the same session regarding the absolute changes ( delta ) of sbp , dbp and map during the 24 hours after the 
 experimental sessions .
a reduction in sbp was observed in the periods 02 h ( 4.8 mmhg ) , 
 46  h ( 7.6 mmhg ) , 68 h ( 11.6 mmhg ) post - max compared to con ( 02 h : + 5.6 ; 46 h : + 6.3 ; 
 68 h : + 9.1 ; 2022 : 1.4 mmhg ) , and in the period 2022 h ( 16.1 mmhg ) compared to the con 
 ( 1.4 mmhg ) and mod ( 2.1 mmhg ) ( p<0.05 ) .
furthermore , a reduction in sbp occurred 
 between 1622 h ( 1618 h : 19.7 mmhg ; 1820 h : 17.6 mmhg ; 2022 h : 16.1 mmhg ) after max 
 compared to pre - exercise rest ( p<0.05 ) .
significant reductions in dbp were observed from 02 h ( 1.9 mmhg ) , 68 h ( 5.8 mmhg ) , and 
 1822 h ( 1820 h : 12.2 mmhg ; 2022 h : 7.5 mmhg ) post - max compared to con ( 02 h : + 7.6 ; and 
 68 h : + 5.0 ; 1820 h : 3.7 ; 2022 h : + 2.4 mmhg ) ( p<0.05 ) . a nocturnal reduction in dbp 
 between 16 and 20  h ( 1618 : 14.5 ; 1820 h : 12.2 mmhg )
similarly the map , significant reductions were observed post - max when compared to con in 
 the periods 02 h ( max : 3.9 vs. con : + 6.6 mmhg ) , 68 h ( max : 7.9 vs. con : + 4.6 mmhg ) , and 
 1822 h [ max ( 1820 h ) : 17.1 vs. con : 7.0 mmhg ; max ( 2022 h ) : 10.4 vs. con : + 0.5 mmhg ] . 
 between 14 and 22  h ( 1416 h : 11.2 ; 1618 h : 16.4 ; 1820 h : 17.1 ; 2022 h : 10.4 mmhg ) 

there was a post - max reduction in map , as well as between 16 and 20  h ( 1618 h : 12.1 ; 1820 
 h : 11.0 mmhg ) post - mod compared to pre - exercise values ( p<0.05 ) .
no significant differences were found for sbp , dbp and map after the mod session compared 
 to after the max and con sessions during the 24  h abpm ( p>0.05 ) .
the present study investigated the effects of different exercise intensities on 24 hour bp 
 responses in patients with t2d and prehypertension .
the results reveal that , when compared 
 to the day in which no exercise was performed ( con ) , the max session elicited a reduction in 
 sbp , dbp and map over a 24  h period .
furthermore , the max session produced a significant 
 reduction in pressure variation during sleep compared to the con session , and also for sbp 
 when compared to the mod session ( table 3 ) .
the majority of studies have investigated the effects of different exercise intensities on 
 24-hour bp responses in healthy and hypertensive subjects21 , 24 .
little research of this 
 type has investigated individuals with t2d15 , 16 , and when it has , the authors only 
 analyzed bp for 2  h post - exercise . therefore , little is known about the effects of different 
 exercise intensities on non - pharmacologic control of 24  h bp in t2d individuals . in the 
 present study ,
both the max and mod sessions elicited significant bp reductions , suggesting 
 that about 20 minutes of exercise has significant benefits .
the results also suggest that 
 the intensity of the exercise and the physiological stress generated play important roles in 
 lowering the blood pressure of individuals with t2d .
evidence has been presented that exercise intensity influences the bp response of diabetic 
 and hypertensive individuals14 , 21 . however , pescatello et al.22 investigated the effects of exercise intensity ( 40 and 70% 
 vo2max ) on the bp response of normotensive and hypertensive individuals , and 
 found that intensity did not affect post - exercise bp reduction , which lasted for 12 hours 
 regardless of the intensity , but only in the hypertensive group . nevertheless , it is 
 possible that the studied intensities ( 40 and 70% of vo2max ) , both within in the 
 same intensity domain ( moderate - below the lt ) , masked the effect of exercise intensity .
eicher et al.24 conducted three 
 experimental sessions of low intensity exercise ( 40% of vo2peak ) , moderate 
 intensity exercise ( 60% of vo2peak ) and vigorous intensity exercise ( 100% of 
 vo2peak ) , with 45 hypertensive men .
they reported that peh was proporcionate to 
 the level of effort in the exercise sessions : the vigorous session caused the greatest 
 reductions in sbp ( 1.0  1.7 mmhg ) and dbp ( 6.3  1.2 mmhg ) compared to the control 
 session ( 10.7  1.3 and 1.4  0.9 mmhg ) .
they also reported that for each 10% increase in 
 vo2peak there was a 1.5 mmhg and 0.6 mmhg decrease for sbp and dbp , 
 respectively .
one of the main features of the present study was that t2d patient results were recorded 
 for 24 hours , and that , compared to con , a greater reduction in sbp occurred during the 
 post - max sleeping period than during post - mod .
this is important for individuals with t2d , 
 considering that elevated bp values during the day associated with a low nocturnal decrease 
 ( less than 10% ) are factors that , in association with hyperglycemia , increase the risk of 
 cardiovascular dysfunction .
jones et al.37 studied 6 normotensive individuals who performed aerobic exercises 
 at 40% and 70% vo2max in the morning , and observed a map reduction only during 
 sleep after 70% vo2max exercise , which suggests that the exercise intensity could 
 have been responsible for this result . the difference in exercise intensity in this study ( max and mod )
can be confirmed by the 
 different levels of metabolic , hemodynamic , and cardiorespiratory stress , and by the 
 perceptual responses collected during the experimental sessions .
significant differences 
 were observed in the responses to max , with higher values of vo2peak , sbp and hr 
 during the session ( table 1 ) . at the end of mod , 

the rpe was 11 and [ lac ] was 3.8  mm , whereas at the end of max the rpe reached 19 , and [ lac ] 
 was 6.7  mm , which shows that max was performed at a higher intensity than mod .
according to 
 macdonald et al.43 , the hemodynamic 
 stress and metabolite accumulations induced by exercise are among the main factors 
 responsible for muscle vasodilatation , and consequently for the decrease in peripheral 
 vascular resistance during and after exercise .
piepoli et al.38 conducted three 
 experimental sessions of maximal incremental exercise with 25  w increments every 5  min , 
 moderate exercise with 5 stages at the 1215 w load , and constant minimal exercise at 50  w 
 of the same duration as the maximal exercise , and a control session with 8 healthy 
 individuals . after exercising
, the participants remained for 60 minutes at the facility for 
 bp , peripheral vascular resistance and forearm vascular resistance analysis .
piepoli et 
 al.38 concluded that , compared to the 
 moderate , minimal and control sessions , only maximal exercise was effective at reducing dbp . 

this finding was probably due to decreases in peripheral vascular resistance and forearm 
 vascular resistance , which remained lower for 1  h only after maximal exercise .
piepoli et 
 al.39 also reported that , after ten 
 healthy individuals performed a maximal exercise session , their dbp was reduced for one 
 hour , probably because of a decrease in peripheral vascular resistance ( as cited above ) , 
 even though there was an increase in renin activity , persistent sympathetic activity and 
 reduced vagal tone , possibly due to peripheral vasodilatation .
reductions in cardiac output and 
 decreases in peripheral vascular resistance are associated with the occurrence of peh40 , 41 .
two mechanisms have been proposed for explaining the post exercise 
 decrease of peripheral resistance : sympathetic inhibition , and alterations in vascular 
 responsiveness .
the activation of the neurokinin-1 receptor during exercise triggers the 
 receptor to undergo internalization after the completion of exercise , dampening the gaba 
 interneuron s solitary tract nucleus , and modifying the baroreflex to a lower level after 
 exercise , by reducing transmission to baroreceptor second - order neurons , increasing the 
 excitement of the ventral caudal lateral medulla , increasing inhibition of the rostral 
 ventral lateral medulla , inhibiting its action , and decreasing sympathetic nervous activity , 
 leading to post - exercise hypotension . on the other hand , a greater local release of nitric 
 oxide , prostaglandins , adenosines , and atp
t2d patients can present endothelial dysfunction2 and reduced release of vasodilator substances , which suggests that a 
 possible mechanism for the decrease of vascular resistance is damaged in this population , as 
 observed in the post - mod response .
nevertheless , after max this limitation would be less 
 evident , as was demonstrated in the present study of t2d patients .
perhaps exercise 
 performed at higher intensities allows greater recruitment of motor units and , consequently , 
 induces greater metabolic and hemodynamic stress , as well as promoting greater bp decrease 
 in the post - exercise period .
the american college of sports medicine9 
 recommends moderate intensity exercise for individuals with t2d , but higher intensity 
 exercise may have additional benefits for cardiorespiratory fitness and glucose control44 .
maximal exercise is a very well known and 
 useful method for verifying exercise response .
thus , its use is important for determining 
 the response of special populations such as t2d patients , considering that these individuals 
 tend to present more cardiovascular problems5 .
nevertheless , it is important to point out that the use of high 
 intensity exercise with t2d patients should be well supervised , and performed only by 
 individuals whose bp and t2d are controlled and who have no associated complications such as 
 cardiovascular dysfunction , and should be used only after having proven the patient s 
 physical and cardiorespiratory fitness in clinical examinations .
finally , we conclude that a single aerobic exercise session resulted in bp reduction for 
 24  h in individuals with t2d , particularly while sleeping , and the magnitude of this 
 reduction seems to be dependent on the intensity at which the exercise is performed .
 [ purpose ] to verify the effects of different intensities of aerobic exercise on 24-hour 
 ambulatory blood pressure ( bp ) responses in individuals with type 2 diabetes mellitus 
 ( t2d ) and prehypertension . 
 [ subjects and methods ] ten individuals with t2d and 
 prehypertension ( 55.8  7.7  years old ; blood glucose 133.0  36.7  mgdl1 and 
 awake bp 130.6  1.6/ 80.5  1.8 mmhg ) completed three randomly assigned experiments : 
 non - exercise control ( con ) and exercise at moderate ( mod ) and maximal ( max ) intensities . 
 heart rate ( hr ) , bp , blood lactate concentrations ( [ lac ] ) , oxygen uptake ( vo2 ) , 
 and rate of perceived exertion ( rpe ) were measured at rest , during the experimental 
 sessions , and during the 60  min recovery period . after this period , ambulatory blood 
 pressure was monitored for 24  h. [ results ] the results indicate that [ lac ] ( max : 6.72.0 
 vs. mod : 3.81.2  mm ) , rpe ( max : 191.3 vs. mod : 112.3 ) and vo2peak ( max : 
 20.24.1 vs. mod : 14.03.0  mlkg1min1 ) were highest following the 
 max session . compared with con , only max elicited post - exercise bp reduction that lasted 
 for 8  h after exercise and during sleep . 
 [ conclusion ] a single session of aerobic exercise 
 resulted in 24  h bp reductions in individuals with t2d , especially while sleeping , and 
 this reduction seems to be dependent on the intensity of the exercise performed . 
INTRODUCTION
SUBJECTS AND METHODS
Statistical analyses
RESULTS
DISCUSSION