Cardiovascular exercise strengthens the heart and improves circulation, but most people struggle to fit regular workouts into their day. Short bursts of vigorous activity, sometimes called exercise snacks, can raise the heart rate and deliver meaningful health benefits. Accurate, real time monitoring of cardio exercises is essential to ensure that these workouts meet recommended intensity and rest guidelines. This paper proposes a Tiny Machine Learning (TinyML) wearable system that tracks the duration and type of common cardio exercises in real time. A compact device containing a six axis inertial measurement unit (IMU) is worn on the arm. The device streams accelerometer data to an on device neural network model, which classifies exercises such as jumping jacks, squat jumps, jogging in place, and a resting state. The TinyML model is trained with labelled motion data and deployed on a microcontroller using quantization to meet memory and latency constraints. Preliminary tests with ten participants show that the system correctly recognizes the targeted exercises with around 95% accuracy and an average F1 score of 0.93 while maintaining inference latency below 100 ms and a memory footprint under 60 KB. By prompting users to alternate 30–60 s of high intensity exercise with rest periods, the device can structure effective interval routines. This work demonstrates how TinyML can enable low cost, low power wearables for personalised cardiovascular exercise monitoring.