function bp_activity_heartbeat_strings( $strings = array() ) {

	if ( ! bp_activity_do_heartbeat() ) {
		return $strings;
	}

	$global_pulse = 0;

	/**
	 * Filter that checks whether the global heartbeat settings already exist.
	 *
	 * @since 2.0.0
	 *
	 * @param array $value Heartbeat settings array.
	 */
	$heartbeat_settings = apply_filters( 'heartbeat_settings', array() );
	if ( ! empty( $heartbeat_settings['interval'] ) ) {
		// 'Fast' is 5
		$global_pulse = is_numeric( $heartbeat_settings['interval'] ) ? absint( $heartbeat_settings['interval'] ) : 5;
	}

	/**
	 * Filters the pulse frequency to be used for the BuddyPress Activity heartbeat.
	 *
	 * @since 2.0.0
	 *
	 * @param int $value The frequency in seconds between pulses.
	 */
	$bp_activity_pulse = apply_filters( 'bp_activity_heartbeat_pulse', 15 );

	/**
	 * Use the global pulse value unless:
	 * a. the BP-specific value has been specifically filtered, or
	 * b. it doesn't exist (ie, BP will be the only one using the heartbeat,
	 *    so we're responsible for enabling it)
	 */
	if ( has_filter( 'bp_activity_heartbeat_pulse' ) || empty( $global_pulse ) ) {
		$pulse = $bp_activity_pulse;
	} else {
		$pulse = $global_pulse;
	}

	$strings = array_merge( $strings, array(
		'newest' => __( 'Load Newest', 'buddypress' ),
		'pulse'  => absint( $pulse ),
	) );

	return $strings;
}