***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: Background Hypertension is a complex chronic condition characterized by elevated arterial blood pressure . Management of hypertension includes non-pharmacologic strategies , which may include techniques that effectively reduce autonomic sympathetic activity . Respiratory exercises improve autonomic control over cardiovascular system and attenuate muscle metaboreflex . Because of these effects , respiratory exercises may be useful to lower blood pressure in subjects with hypertension . Methods / design This r and omized , double-blind clinical trial will test the efficacy of inspiratory muscle training in reducing blood pressure in adults with essential hypertension . Subjects are r and omly allocated to intervention or control groups . Intervention consists of inspiratory muscle training loaded with 40 % of maximum inspiratory pressure , readjusted weekly . Control sham intervention consists of unloaded exercises .  Systolic and diastolic blood pressures are co- primary endpoint measures assessed with 24 h ambulatory blood pressure monitoring . Secondary outcome measures include cardiovascular autonomic control , inspiratory muscle metaboreflex , cardiopulmonary capacity , and inspiratory muscle strength and endurance . Discussion Previously published work suggests that inspiratory muscle training reduces blood pressure in persons with hypertension , but the effectiveness of this intervention is yet to be established . We propose an adequately sized r and omized clinical trial to test this hypothesis rigorously . If an effect is found , this study will allow for the investigation of putative mechanisms to mediate this effect , including autonomic cardiovascular control and metaboreflex . Trial registration Clinical Trials.gov NCT02275377 . Registered on 30 September 2014 Objective : To evaluate heart rate variability during an inspiratory muscle endurance protocol at three different load levels [ 30 % , 60 % and 80 % of maximal inspiratory pressure ] , in patients who had previously undergone coronary artery bypass grafting . Methods : Nineteen late postoperative myocardial revascularization patients participating in a cardiovascular rehabilitation program were studied .  Maximal inspiratory pressure maneuvers were performed . An inspiratory muscle endurance protocol at 30 % , 60 % and 80 % of maximal inspiratory pressure was applied for four minutes each , in r and om order . Heart rate and RR intervals were recorded and heart rate variability was analyzed by time ( RMSSD-the mean of the st and ard deviations for all R-R intervals , and RMSM-root-mean square differences of successive R-R intervals ) and frequency domains indices ( high and low frequency ) in normalized units . ANOVA for repeated measurements was used to compare heart rate variability indices and Student t-test was used to compare the maximal inspiratory pressure and maximal expiratory pressure values . Results : Heart rate increased during performance of maximal respiratory pressures maneuvers , and the maximal inspiratory pressure and maximal expiratory pressure mean values were significantly lower than predicted values ( P<0.05 ) . RMSSD increased significantly at 80 % in relation to rest and 30 % of maximal inspiratory pressure and RMSM decreased at 30 % and 60 % of maximal inspiratory pressure in relation to rest ( P<0.05 ) . Additionally , there was significant and progressive decrease in low frequency and increase in high frequency at 30 % , 60 % and 80 % of maximal inspiratory pressure in relation to the resting condition . Conclusion : These results suggest that respiratory muscle training at high intensities can promote greater parasympathetic activity and it may confer important benefits during a rehabilitation program in post-coronary artery bypass grafting Introduction Cardiac surgery is a highly complex procedure which generates worsening of lung function and decreased inspiratory muscle strength . The inspiratory muscle training becomes effective for muscle strengthening and can improve functional capacity . Objective To investigate the effect of inspiratory muscle training on functional capacity submaximal and inspiratory muscle strength in patients undergoing cardiac surgery . Methods This is a clinical r and omized controlled trial with patients undergoing cardiac surgery at Instituto Nobre de Cardiologia . Patients were divided into two groups : control group and training . Preoperatively , were assessed the maximum inspiratory pressure and the distance covered in a 6-minute walk test . From the third postoperative day , the control group was managed according to the routine of the unit while the training group underwent daily protocol of respiratory muscle training until the day of discharge . Results 50 patients , 27 ( 54 % ) males were included , with a mean age of 56.7±13.9 years . After the analysis , the training group had significant increase in maximum inspiratory pressure ( 69.5±14.9 vs. 83.1±19.1 cmH2O , P=0.0073 ) and 6-minute walk test ( 422.4±102.8 vs. 502.4±112.8 m , P=0.0031 ) . Conclusion We conclude that inspiratory muscle training was effective in improving functional capacity submaximal and inspiratory muscle strength in this sample of patients undergoing cardiac surgery Background Physical exercise reduces glucose levels and glucose variability in patients with type 2 diabetes .  Acute inspiratory muscle exercise has been shown to reduce these parameters in a small group of patients with type 2 diabetes , but these results have yet to be confirmed in a well- design ed study . The aim of this study is to investigate the effect of acute inspiratory muscle exercise on glucose levels , glucose variability , and cardiovascular autonomic function in patients with type 2 diabetes . Methods / design This study will use a r and omized clinical trial crossover design . A total of 14 subjects will be recruited and r and omly allocated to two groups to perform acute inspiratory muscle loading at 2 % of maximal inspiratory pressure ( PImax , placebo load ) or 60 % of PImax ( experimental load ) . Discussion Inspiratory muscle training could be a novel exercise modality to be used to decrease glucose levels and glucose variability . Trial registration Clinical Trials.gov NCT02292810 BACKGROUND The cardiovascular system is noticeably affected by respiration . However , whether different inspiratory resistive loading intensities can influence autonomic heart rate ( HR ) modulation remains unclear . OBJECTIVE The objective was to investigate HR modulation at three different inspiratory resistive loading intensities in healthy elderly men . METHOD This was a prospect i ve , r and omized , double-blind study that evaluated 25 healthy elderly men . Cardiac autonomic modulation was assessed using heart rate variability ( HRV ) indices . All of the volunteers underwent maximal inspiratory pressure  ( MIP ) measurements according to st and ardized pulmonary function measurements . Three r and omly-applied inspiratory resistive loading ( 30 , 60 and 80 % of MIP ) intensities were then applied using an inspiratory resistance device ( POWERbreathe , Southam , UK ) , during which the volunteers were asked to inhale for 2 seconds and exhale for 3 seconds and complete 12 breaths per minute . Each effort level was performed for 4 minutes , and HR and the distance between 2 subsequent R waves of electrocardiogram ( R-R intervals ) were collected at rest and at each intensity for further HRV analysis . RESULTS The parasympathetic HRV ( rMSSD , SD1 and HF ) indices demonstrated lower values at 80 % ( rMSSD : 19±2 ms , SD1 : 13±2 ms and HF : 228±61 ms2 ) than at 30 % MIP ( rMSSD : 25±3 ms , SD1 : 18±2 ms and HF : 447±95 ms2 ; p<0.05 ) . CONCLUSIONS Lower inspiratory resistive loading intensities promoted a marked and positive improvement of parasympathetic sinus node modulation The crural diaphragm ( CD ) is an essential component of the esophagogastric junction ( EGJ ) , and inspiratory exercises may modify its function . This study 's goal is to verify if inspiratory muscle training ( IMT ) improves EGJ motility and gastroesophageal reflux ( GER ) .  Twelve GER disease [ GERD ; 7 males , 20 - 47 yr , 9 esophagitis , and 3 nonerosive reflex disease ( NERD ) ] and 7 healthy volunteers ( 3 males , 20 - 41 yr ) performed esophageal pH monitoring , manometry , and heart rate variability ( HRV ) studies . A 6-cm sleeve catheter measured average EGJ pressure during resting , peak inspiratory EGJ pressures during  sinus arrhythmia maneuver ( SAM ) and inhalations under 17- , 35- , and 70-cmH2O loads ( TH maneuvers ) , and along 1 h after a meal . GERD patients entered a 5-days-a-week IMT program . One author scored heartburn and regurgitation before and after IMT . IMT increased average EGJ pressure ( 19.7 ± 2.4 vs. 29.5 ± 2.1 mmHg ; P < 0.001 ) and inspiratory EGJ pressure during SAM ( 89.6 ± 7.6 vs. 125.6 ± 13.3 mmHg ; P = 0.001 ) and during TH maneuvers . The EGJ-pressure gain across 35- and 70-cmH2O loads was lower for GERD volunteers . The number and cumulative duration of the transient lower esophageal sphincter relaxations decreased after IMT . Proximal progression of GER decreased after IMT but not the distal acid exposure . Low-frequency power increased after IMT and the higher its increment the lower the increment of supine acid exposure . IMT decreased heartburn and regurgitation scores . In conclusion , IMT  improved EGJ pressure , reduced GER proximal progression , and reduced GERD symptoms . Some GERD patients have a CD failure , and IMT may prove beneficial as a GERD add-on treatment OBJECTIVES This study sought to evaluate the effects of inspiratory muscle training in inspiratory muscle strength , as well as in functional capacity , ventilatory responses to exercise , recovery oxygen uptake kinetics , and quality of life in patients with chronic heart failure ( CHF ) and inspiratory muscle weakness . BACKGROUND Patients with CHF may have reduced strength and endurance in inspiratory muscles , which may contribute to exercise intolerance and is associated with a poor prognosis . METHODS Thirty-two patients with CHF and weakness of inspiratory muscles ( maximal inspiratory pressure [ Pi(max ) ] < 70 % of predicted ) were r and omly assigned to a 12-week program of inspiratory muscle training ( IMT , 16 patients ) or to a placebo-inspiratory muscle training ( P-IMT , 16 patients ) . The following measures were obtained before and after the program : Pi(max ) at rest and 10 min after maximal exercise ; peak oxygen uptake , circulatory power , ventilatory oscillations , and oxygen kinetics during early recovery ( VO2/t-slope ) ; 6-min walk test ; and quality of life scores . RESULTS The IMT result ed in a 115 % increment Pi(max ) , 17 % increase in peak oxygen uptake , and 19 % increase in the 6-min walk distance . Likewise , circulatory power increased and ventilatory oscillations were reduced . The VO2/t-slope was improved during the recovery period , and quality of life scores improved . CONCLUSIONS In patients with CHF and inspiratory muscle weakness , IMT results in marked improvement in inspiratory muscle strength , as well as improvement in functional capacity , ventilatory response to exercise , recovery oxygen uptake kinetics , and quality of life Autonomic dysfunction , including baroreceptor attenuation and sympathetic activation , has been reported in patients with myocardial infa rct ion ( MI ) and has been associated with increased mortality . We tested the hypotheses that exercise training ( ET ) in post-MI patients would normalize arterial baroreflex sensitivity ( BRS ) and muscle sympathetic nerve activity ( MSNA ) , and long-term ET would maintain the benefits in BRS and MSNA . Twenty-eight patients after 1 month of uncomplicated MI were r and omly assigned to 2 groups , ET ( MI-ET ) and untrained . A normal control group was also studied . ET consisted of three 60-minute exercise sessions per week for 6 months . We evaluated MSNA ( microneurography ) , blood pressure ( automatic oscillometric method ) , heart rate ( ECG ) , and spectral analysis of RR interval , systolic arterial pressure ( SAP ) , and MSNA . Baroreflex gain of SAP-RR interval and SAP-MSNA were calculated using the & agr;-index . At 3 to 5 days and 1 month after MI , MSNA and low-frequency SAP were significantly higher and BRS significantly lower in MI patients when compared with the normal control group . ET significantly decreased MSNA ( bursts per 100 heartbeats ) and the low-frequency component of SAP and significantly increased the low-frequency component of MSNA and BRS of the RR interval and MSNA . These changes were so marked that the differences between patients with MI and the normal control group were no longer observed after ET .  MSNA and BRS in the MI-untrained group did not change from baseline over the same time period . ET  normalizes BRS , low-frequency SAP , and MSNA in patients with MI . These improvements in autonomic control are maintained by long-term ET . These findings highlight the clinical importance of this nonpharmacological therapy based on ET in the long-term treatment of patients with MI PURPOSE Patients with type 2 diabetes mellitus may present weakness of the inspiratory muscles . We tested the hypothesis that inspiratory muscle training ( IMT ) could improve inspiratory muscle strength , pulmonary function , functional capacity , and autonomic modulation in patients with type 2 diabetes and weakness of the inspiratory muscles . M 
    Output:
    
The results demonstrated that IMT performed at low intensities can chronically promote an increase in the parasympathetic modulation and /or reduction of sympathetic cardiac modulation in patients with diabetes , hypertension , chronic heart failure and gastroesophageal reflux , when assessed by HRV spectral analysis .