This work is devoted to the comparative analysis two approaches for investigation of energy dissipation in metal under fatigue crack propagation. The flat specimens with V-shaped stress concentrators from steel 304 AISE and titanium alloy Grade 2 were tested. The dissipated energy was measured using both original contact heat flux sensor and IR camera FLIR SC5000. The results of IR monitoring were analysed with a goal to estimate the amplitude of second temperature harmonics (D-mode). As a result of the study, we have shown that the dissipated energy values estimated by both methods have a good qualitative agreement. The measured values allows us to propose a correlation between the crack rate and dissipated energy for predicting the fatigue crack growth.