School of Science, Medicine & Health Michael J Macartney. Supervised By: Dr Gregory Peoples Prof Peter McLennan Mr Marc Brown

Transcription

1 School of Science, Medicine & Health 2013 Michael J Macartney Supervised By: Dr Gregory Peoples Prof Peter McLennan Mr Marc Brown

2 The Cardiac Branch The Vascular Branch Blood Pressure = CVD & all-cause mortality risk (Palatini P., et al 2009, Zhang & Zhang., 2009) Heart rate = CVD & allcause mortality risk (Palatini P., et al 2009, Cook & Togni., 2006, Ivanovid., et al 2012) Heart rate variability = CVD mortality (Tsuji & Larson., et al 1996) Slower heart rate recovery correlates with cardiac mortality (Jouven & Empana., et al 2005)

3 Peak HR ( bpm) Sub-Max HR (80-160bpm) Heart Rate Recovery Fish oil supplementation shows potential to improve heart rate recovery in myocardial infarction patients. (O Keefe et al., 2006) Therapeutic dose (6-8g/day) fish oil supplementation has been demonstrated to reduce sub-maximal heart rate. No effect peak heart rate (Peoples & McLennan., 2008) (Buckley et al., 2009) Resting HR (40-80bpm) Fish oil supplementation in humans resulted in a reduction of resting heart rate by 1.6beats.min -1. (Mozaffarian et al., 2005)

4 The overall aim of this study, was to investigate the role of dietary achievable fish oil on cardiac function, under resting, exercise induced stress and recovery conditions, in a subject group with a fit and healthy background. Experimental Overview: Subject Recruitment Male 18-40yrs (N=39) Baseline RBC fatty acid and resting cardiovascular (CV) measurements Repeat bout cycling protocol Split into supplement groups based on matching data (n=14)* Presupplementation Postsupplementation RBC fatty acid measurements Repeat bout cycling protocol and resting CV measures * Each group consumed 2x1g capsules/day of either soy bean oil for control group or fish oil containing a total of 560mg of DHA and 140mg of EPA Omega-3 PUFA.

5 R e la tiv e % o f E ry th r o c y te F a tty A c id s 8 c d c d c = Significant difference within group after supplementation (FO post v FO pre) (p<0.0001). d = Significant difference between groups after supplementation (FO post v Control post) (p<0.0001) 6 Fatty acid key: 20:5n-3 = Eicosapentaenoic acid (EPA) 22:6n-3 = Docosahexaenoic acid (DHA) n-3 Index = DHA + EPA 4 F is h O il P re 2 F is h O il P o s t C o n tro l P re C o n tro l P o s t 0 D H A n - 3 In d e x

6 H e a r t R a te (b e a ts.m in -1 ) H e a r t R a te (b e a ts.m in -1 ) 6 5 a 7 0 F is h O il b C o n tro l 8 0 C o n tro l F is h O il c d L a b h e a r t r a te A w a k e S u p in e h e a r t r a te M e a n h e a r t r a te S le e p in g M in im u m h e a r t r a te 0 P r e - s u p p le m e n t P o s t - s u p p le m e n t No significant differences within conditions between control and FO group following supplementation. a,b,c,d = Significant differences (p<0.05) between all baseline measured conditions.

7 C h a n g e S D 1 :S D C o n t r o l F is h O il Trending reduction for fish oil group (p=0.18). p<0.05 set as critical value.

8 T o ta l B e a t C h a n g e Reduction of 22 beats over 5 minutes is an average of 4.5beats.min -1 less C o n tro l F is h O il F ir s t 5 m in * S e c o n d 5 m in * = Significant less total beats (FO post v Control post supplementation) min 5-10 (P=0.005).

9 H e a r t R a te (b p m ) L o g H R N o d iffe r e n c e a t p e a k N e t R e c o v e r y H e a rt R a te N o d iffe r e n c e a t 1 0 t h m in P e a k R e c o v e ry T im e (s e c s ) M in u te Representative (subject 007) graph of net recovery heart rate during supine recovery. Notes: No significant differences between FO and control group at the start point (peak heart rate) or end point (10 th minute) of recovery. p<0.05 set as critical value.

10 L o g it H e a r t R a te L o g it H e a r t R a te C o n tro l P re F is h O il P re C o n tro l P o s t lo g t 1 /2 F is h O il P o s t lo g t 1 / t 1 / 2 (p r e ) : s t 1 / 2 (p r e ) : s t 1 /2 (p o s t ) : s * t 1 /2 (p o s t ) : s L o g T im e Control Logit HR vs. Log recovery time * L o g T im e Fish Oil Logit HR vs. Log recovery time. Notes: Values expressed as (means ±SE) for post-exercise (5 min work capacity trial). The value of log time at logit = 0 corresponds to log half-recovery time (log t½). Absolute time(s) of t½ inset on graph.

11 The current study demonstrated that fish oil; resulted in DHA membrane incorporation. did not true resting HR. resulted in the capacity to HR under exercise induced stress. produced a more rapid HR recovery profile. These effects are most likely explained by a direct effect of fish oil on the cardiac intrinsic rate. (Laustiola, Salo et al., 1986; McLennan., 2001; Pepe & McLennan., 2002; Harris, Gonzales et al., 2006)

12 HR & slowed HRR is a risk factor for CVD and all-cause mortality. HR results in myocardial perfusion time. Most importantly, the effects demonstrated in this study were still evident despite the fact an already very fit and healthy subject population; along with dietary achievable (1 x 250g salmon meal/week) fish oil supplementation intake was used.